If w is divisible by 15 and 9, w must be a…

If w is divisible by 15 and 9, w must be a multiple of which of the following?

This problem repeats another one in the library (at most with different numbers), so it's left out of browsing.

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · train #51808