Assume a Cobb-Douglas Production Function Where the Share of Capital

Assume a Cobb-Douglas production function where the share of capital and labor is each 1/2.If the growth in total factor productivity is zero and labor and capital each grow by 2%, then

A) output growth is 4% and the marginal product of capital is Y/K
B) output growth is 2% and the marginal product of capital is Y/(2K)
C) output growth is 2% and the marginal product of labor is (2Y) /N
D) output growth is 1% and the marginal product of labor is Y/(2N)
E) output growth is 1% and the marginal product of capital is (2Y) /K