Who holds the record for scoring highest run score in an inning of test match?

The correct answer is: Don Bradman.

Don Bradman scored 334 runs in the 6th innings of the 3rd Test match against England at Headingley, Leeds in 1930. This is the highest individual score in a Test innings.

Matthew Hayden scored 380 runs in the 2nd innings of the 1st Test match against Zimbabwe at the Gabba, Brisbane in 2003. This is the second highest individual score in a Test innings.

Mahela Jayawardene scored 374 runs in the 1st innings of the 3rd Test match against South Africa at the Sinhalese Sports Club Ground, Colombo in 2006. This is the third highest individual score in a Test innings.

None of these is the correct answer.