[Q]: cause?

The bird couldn't fly.

OPTIONS:
- It migrated for the winter.
- It injured its wing.
****
[A]: It injured its wing.

[Q]: cause?

I approached the man.

OPTIONS:
- He looked busy.
- He looked familiar.
****
[A]: He looked familiar.

[Q]: effect?

My favorite song came on the radio.

OPTIONS:
- I covered my ears.
- I sang along to it.
****
[A]:
I sang along to it.