💡 Detailed Explanation
'Satchi' (察知) means to sense or perceive something that is not explicitly stated, such as an atmosphere, danger, or someone's feelings. Choice 1 is correct as it describes sensing a change in someone's feelings. The other choices would be more appropriately expressed with verbs like 'rikai suru' (to understand) for 2, 'shirasareru/kiku' (to be informed/to hear) for 3, and 'handan suru' (to judge) for 4.