Questions & Answers about Ana se gândește la plan.
Because the verb here is a se gândi la, which means to think about.
In Romanian, se is the reflexive pronoun used with he/she/it and with names like Ana. So:
- Ana se gândește = Ana thinks / is thinking
- Ea se gândește = She thinks / is thinking
With other persons, the reflexive pronoun changes:
- mă gândesc = I think / am thinking
- te gândești = you think / are thinking
- ne gândim = we think / are thinking
So se is not optional here.