A statistical question is one that anticipates variability in the data and usually involves summarizing or analyzing information from a group.
The question that qualifies as a statistical question from your options is:
What are the ages of the singers in the community chorus?
This question seeks information about the ages of multiple individuals, acknowledging that there will be a range of ages (i.e., variability). The other questions either seek specific answers about individual singers or do not imply variability.