Answer: I learned to swim
Explanation:
✗ I am learning to swim ➜ This is present progressive, a form of be + -ing.
✗ I learn to swim ➜ This is present tense, "I learn" is happening as it's said.
✓ I learned to swim ➜ This is past tense, it already happened.
✗ I will learn to swim ➜ This is future test, it will happen but has not yet.
