Examine the nuclear reaction: 1 1 h+ 1 0 n -> 2 1 h.

1) Conversion of an isotope one chemical element or an isotope into another chemical element is called as nuclear transmutation.

2) In a nuclear transmutation reactions can be achieved either due to radioactive decay or  due to nuclear reactions. 

3) In this technique, it is possible to convert a stable element into radioactive atom by bombarding in with high speed particles. The initial stable nuclei is referred as parent nuclei, the fast moving particle is referred as projectile while new element which is formed is called as daughter element.

4) In the present reaction:
                                        1 1 H+ 1 0 n -> 2 1 H
1 1H is a parent nuclei which is bombarded with the fast moving projectile
(1 0 n) to generate a new daughter nuclei (2 1H). 

Most likely a is the answer - because  you generate   38 atp's but also consume an atp.   each atp gives approx. less than 4 kcal so probably a is the closest answer.