Within each "unit" composing a shoot of a vascular plant, you would observe leaves attached at the and a large stretch of stem without leaves at the

Node; internode

Leaf has point of attachment at the primary stem which is the node. Each leaf form an axillary bud. Lateral branches came from this axillary bud. Thus, a lateral branch arises from a node. Nodes are important part of the plant where healing, structural support and other biological processes happens. 

Internode is the distance from one node to the other. This add to the height of the plant. This is important as this hold the vessels that bring water and nutrients to the other parts of the plant.

The correct answer is c