[单选题]
The temperature of an 2p 1gaa bza34rideal gas increases kw(n87mp mz0,0du i2f8mtvcefrom $2 \; ^{\circ}C$ to $4 \; ^{\circ}C$ while remaining at constant pressure. What happens to the volume of the gas?
A. It decreases slightly.
B. It decreases to one-half its original volume.
C. It increases slightly.
D. It increases to twice as much.
