The length of the rod will become exactly half of its original value.

The length of the rod remains the same.

The length of the rod will decrease.

The length of the rod will increase.

Wouldn't the length double, thus being answer D?

1 answer

If your question is:
If a rod is moving at a velocity equal to 1/2 the speed of light parallel to its length, what will a stationary observer observe about its length?

The answer is
L=L₀•sqrt{1-(v/c)²}=0.866L₀
The length of the rod will decrease.