[单选题]
If you push twice as hard againsvh ;u0z o nmk )ll1745bjcxx3mt a sv 2 6 k(dy ambxl39b,nezu(m,qtationary brick wall, the amount of work youl2 z,9kxnm6 a(bvquyd3b( m,e do
A. doubles.
B. is cut in half.
C. remains constant but non-zero.
D. remains constant at zero.
