Explanation: \((ax)^{16}(by)^{12}(cxy)^{17} (dxy)^{11}>0\) Or, \(a^{16}b^{12}c^{17}d^{11}x^{4}y^{40}>0\) এবার a, b, x y have positive even exponents. So, we cannot say whether just a, b, x or y are positive or negative, since even number exponents always result in a positive number. However, since the entire product is positive, this means that c and d , both of which have odd number exponents, must either both be positive or both be negative. Otherwise, the product would have been a negative number. So, only the product of cd must be positive. Therefore, \(cd>0\). Correct Answer (C)
