In the following list of magmas, only one is likely to explode - the others will produce lava flows or spatter to form small cinder cones or ooze out to form lava domes. Which one of the following magmas is most likely to produce an explosive volcanic eruption when it reaches the Earth's surface?
a. A basaltic magma with gas.
b. A basaltic magma without gas.
c. An andesitic magma with gas.
d. A rhyolitic magma without gas.