Who were the teachers of Karn in Mahabharat

As per Mahabharat, Karn had learnt from 3 gurus and they are Guru Drona, Kripacharya (Brother of Kripi, who is the wife of Drona) and Lord Parashurama.

However, TV serials always show that Karn was rejected Drona because he belonged to the Suta Tribe. There are multiple mentions where it is written that Drona was the teacher of Karn and they are:-

1. Karn in Gurudakshina yudh against Drupad

“Those bulls among men, smiting the Panchalas on their way, laid siege to the capital of the great Drupada. And Duryodhana and Karna and the mighty Yuyutsu, and Duhsasana and Vikarna and Jalasandha and Sulochana,--these and many other foremost of Kshatriya princes of great prowess, vied with one another in becoming the foremost in the attack. And the princes, riding in first class chariots and following the cavalry, entered the hostile capital, and proceeded along the streets.”

“And careering over the field of battle like a fiery wheel, king Drupada with his arrows smote Duryodhana and Vikarna and even the mighty Karna and many other heroic princes and numberless warriors, and slaked their thirst for battle.”

2. Narada mentioning Karn as a student of Drona in Shanti Parva

“For this, a child was conceived by Kunti in her maidenhood, capable of provoking a general war. Endued with great energy, that child came to have the status of a Suta. He subsequently acquired the science of weapons from the preceptor (Drona), that foremost descendant of Angirasa's race.”

3. Mention in Adi Parva

“O bull of the Bharata race, many other princes also flocked to that best of Brahmanas for instruction in arms. The Vrishnis and the Andhakas, and princes from various lands, and the (adopted) son of Radha of the Suta caste, (Karna), all became pupils of Drona. But of them all, the Suta child Karna, from jealousy, frequently defied Arjuna, and supported by Duryodhana, used to disregard the Pandavas.”

4. Karna tells his father, Surya that he is the son of Drona 

Karna said, 'As thou, O lord of splendour, knowest me for thy worshipper……………..Thou knowest, O deity, that I have great strength of weapons obtained from Jamadagnya and the high-souled Drona 

Therefore, we conclude that KARN was actually taught by Dronacharya and he went to Parashurama when Drona did not provide him with the Brahmastra while stating this “The brahmastra can only be known by a brahmana who is observant of the vows, or by a kshatriya who has performed austerities, and by no one else.” -1330(2). 

Therefore Karn went to Lord Parashuram and got the Brahmastra by deceit as a result of which he got a curse. This is what Lord Parashurama had said:- 

"You have always sought to rival someone (Arjuna) and you have been striving against him every day. Because of this crime, when you are fighting with him, the earth will swallow up the wheel of your chariot. O worst of men! When you clash against your foe and are distracted because the wheel of your chariot has been devoured by the earth, he will exhibit his valor and sever your head. O stupid one! Leave this place. Just as you were distracted when you acted against me, another person will sever and bring down your head while you are distracted."

Also Read:- 
https://dhananjayparth.blogspot.com/2021/03/was-satyaki-able-to-defeat-karna.html
https://dhananjayparth.blogspot.com/2021/03/5-types-of-archery-5-vidhis-of.html
https://dhananjayparth.blogspot.com/2021/03/was-there-any-secret-of-draupadi.html