When a Heavy Metal Block Is Supported by a Cylindrical $\sqrt { 2 }$

When a heavy metal block is supported by a cylindrical vertical post of radius R,it exerts a force F on the post.If the diameter of the post is increased to 2R,what force does the block now exert on the post?

A) F/4
B) F/2
C) F/ $\sqrt { 2 }$
D) F
E) 2F