a, b, c and d are negative integers. If ab + ac + ad = 0 then a × b × c × d is always

Answer: Option B

Given that a^b + a^c + a^d = 0
Hence, out of these three terms, some are positive and some are negative. Since all of a, b, c, and d are negative integers, only that term which has an even power can be positive. Hence, the absolute value of at least one of a, b, c or d is even. Hence, a × b × c × d is also even