Why the answer is B, and why the others tempt you.
Using integration by parts with u = x and dv = eˣ dx: du = dx, v = eˣ. So ∫xeˣ dx = xeˣ - ∫eˣ dx = xeˣ - eˣ + C = eˣ(x-1) + C. Note that options B and C are equivalent, so checking: B = xeˣ - eˣ + C and C = eˣ(x-1) + C = xeˣ - eˣ + C, making both B and C correct. The intended distinct correct answer is B.
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