How do we determine whether it's a capacitor or inductor

Question

A device 'X' is connected to an a.c. source V = V₀ sin wt. The variation of voltage current and power in one complete cycle is shown in the following figure.
1. Which curve shows power consumption over a full cycle?
2. Identify the device 'X'.

how to solve

Answer 1

(a) 'X' is a Capacitor 

(b) Curve A has power consumption