The Images of the Deep Impact Encounter with Comet Tempel

The images of the Deep Impact encounter with Comet Tempel 1 in 2005 (see Figure 8-32,Comins: Discovering the Essential Universe,6th ed.) show the nucleus looking like a solid piece of rock and not like a fiery comet with a glowing tail.Why is the glowing gas we usually associate with a comet absent?

A) This is an unsolved mystery and one of the reasons this comet was chosen for investigation.
B) Comet Tempel 1 is a very old comet, and almost all of the volatile material is gone.
C) A comet evolves glowing gases only when it is near the Sun, and Comet Tempel 1 never gets close enough to the Sun to evolve a tail.
D) Comet Tempel 1 is, in fact, a solid rock and shows no evidence of ice.