Final answer:
When wind strengthens, temperature drops, and air pressure drops, it usually signifies an incoming rainstorm, so the picnic should be moved into a shelter.
Step-by-step explanation:
The correct actions to take if you feel the wind getting stronger, the temperature dropping, and you hear that the air pressure is dropping would be to move the picnic into a shelter because these are signs that rain is likely on the way. This corresponds with answer choice C: Move the picnic into a shelter because rain is on the way. A drop in air pressure typically indicates an approaching storm system. Since the temperature is also dropping, it supports the notion that the weather is changing rather than there simply being a cool evening.