Consider the question. There are 42 distinct numbers in set M, there are 28 distinct numbers in set N, and there are 12 distinct numbers that are in both sets M and N. Set H is the set containing the elements that are in at least one of sets M and N. How many elements are in set H?
Options:
(A) 39
(B) 40
(C) 51
(D) 58
(E) 63
 If the answer is '(D)'; explain the reasoning:
user
{Total} = {M} + {N} - {Both}
{Total} = 42 + 28 - 12 = 58.
assistant