Concept: The question tests on the ability to solve Word problem
Solution:
Let the number of correct answers = x and number of wrong answers = y
x + y = 90
5x - 2y = 387
Putting x = 90 - y from (1) into equation (2), we get 5(90 - y) - 2y = 387
450 - 5y - 2y = 387
7y = 63
y = 9
Option A