Name one pair of rays that are not opposite rays.

ED and EC

Step-by-step explanation:

If the two rays which extend in the opposite direction having same endpoint is said to be opposite rays.

From the picture attached,

Rays having same endpoint E but not in the opposite directions are ED and EC.

This pair of rays meet at point E having different directions.

Similarly EA and EB is the other pair of rays having same end point (at E) but not in opposite directions.  

its 4 because 2 times 2 is 4, if you double the number two you get four