Explanation

Write out sequences until you see the pattern.

The second term in the sequence is 3(–1) = –3.

Adding 3 gives you the third term, 0. Multiplying by –1 gives you the fourth term, also 0.

Adding 3 gives you 3, the fifth term. So the sequence repeats every four terms: 3, –3, 0, 0, 3, –3, 0, 0, and so forth.

Dividing 168 by 4 gives you a remainder of zero, and the fourth, eighth, twelfth, and every other nth term where n is a multiple of 4 (including the 168th term) will all
be the same value, 0. The answer is choice (C).
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