2. Which of the following production functions exhibit constant returns to scale? In each case y is output and K and L are inputs. (1) y = K 1'2 L 1'3. (2) y = 3K \"2 L \"2. (3) y = K 1'2 + L \"2. (4) y = 2K + 3L. (e) a. 1, 2, and 4 b. 2, 3, and 4 c. 1, 3, and 4 d. 2 and 3 e. 2 and 4