26. Which one of the following is not a vector quantity?
(2)
A) acceleration
C) displacement
E) instantaneous velocity
B) average speed
D) average velocity​

Speed is not a vector quantity. It has only magnitude and no direction and hence it is a scalar quantity.

answercollision;

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.