A block of mass (2 kg) is acted upon by two forces: 3 N (directed to the left) and 4 N(directed to the right). What can you say about the block's motion

a). It must be moving to the left.
b). It must be moving to the right.
c). It must be at rest.
d). It could be moving to the left, moving to the right, or be instantaneously at rest.