GMAT Problem Solving (PS) | In a sequence a_1, a_2,…, each term after the first is found by taking

In a sequence \(a_1\),\(a_2\),…, each term after the first is found by taking the negative of the preceding term, and adding 1. If \(a_1\) = 2, what is the sum of the first 99 terms?
(A) 49
(B) 50
(C) 51
(D) 99
(E) 101

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