18. Find the cost function when a firm's production function is f(x, , x2) = (x1/3 + x1/3)3. A. C(w1 , W2, q) = w ,q W ,q + ( 1+ ( 2) 1/2)3 (1 + ( W 1 ) 1/2 ) 3 W 1 W 2 B. C(w1 , W2, q) = wq + (1+ (1)1/2) 3 1+ (2)1/2 ) 3 W 2 W 1 C. C(w, , W2 , q) = wq w , q + ( 1 + ( W1) /2)3 (1 + ( W 1) 1 /2) 3 W 2 W 2 D. C(w1 , W2, q) = wq + (1 + ( W 2) 1/2 )3 (1 + ( W 2) 1/2 ) 3 W , W 1