My answer is C.
Is d negative?
(1) e + d = -12
(2) e – d < -12
From statement 1, we know that d = -12 - e. Thus, d < 0 if and only if e > -12. Not sufficient.
From statement 2, d > e + 12. As e can be either positive or negative, the statement is insufficient.
Taken together, the statements are sufficient. From 1 and 2, we know the following:
d = -12 -e
e < -12 + d
Thus, d < 0 if and only if e > -12. Plugging equation 1 into the inequality yields the following:
e < -24-e
2e < -24
e < -12
Becase e < -12, -12-e will always yield a positive result for d. Thus, from 1 and 2 we know that d cannot be negative.