Which of the following is a null vector
a) velocity vector of a body moving in a circle with a uniform speed
b) velocity vector of a body moving in a straight line with a uniform speed
c) position vector of the origin of the rectangular coordinate system
d) displacement vector of a stationary object

• A

  both a & b

• B

  both b & c

• C

  a, b & c
   

• D

  both c & d