Reading

I'd like to know if my answer "a" is correct. Thank you.
"By far the worst form of competition in schools is the disproportionate emphasis on examinations. It is a rare school that allows pupils t o concentrate on those things they do well . The merits of competition by examination are dubious enough, but competition in the certain knowledge of failure is positively harmful.

What is particularly harmful about examinations?
a. Failure rates are high. c. Unsuitable subjects are set .
b. The wrong students succeed. d. Some students are bound to fail."