What is a volcanic bomb?
A. a very violent volcanic explosion
B. a particle larger than 64 mm in size ejected as glowing lava
C. a pocket of gas that is released suddenly
D. a tiny particle of ejected rock less than 64 mm in size

Volcanic bomb is a particle larger than 64 mm in size ejected as glowing lava.  
Correct answer: BThese masses of molten rock are often found near the vent (due to size) but sometimes propelled great distances. Their shape is determined by the initial size, viscosity, and flight velocity of the lava bomb.

B. Particle larger than 64 mm in size ejected as glowing lava