**Core Concept:** Fixed prepositional phrases (e.g., 'depend on'). **Answer Analysis:** - **B** is correct. 'Depends on' is a fixed collocation meaning 'is determined by'. - **A/C/D** ('with', 'for', 'at') are unidiomatic with 'depends' in this context. **Common Mistakes:** Misremembering common collocations due to similar verbs (e.g., 'rely on' vs. 'wait for').