Answer: D) Philadelphia
Step-by-step explanation:
The top bar as a darker shade represents the population in 1990, and the lighter shade down below is the population for the year 2000.
The city of Dallas has its population increase because the lighter shaded bar is longer. This rules out choice A. Choices B and C are ruled out for similar reasoning (Phoenix and San Diego also show population growth).
Only Philadelphia experiences population decline during this time period.