Present Perfect Simple or Present Perfect Continuous?

Circle the correct answer a or b.

a I’ve started driving lessons.
b I’ve been starting driving lessons.

a I’ve sold my bike to Paul.
b I’ve been selling my bike to Paul.

a Peter has just swum.
b Peter has just been swimming.

a David has cried.
b David has been crying.

a Tim Henmann hasn’t won the Wimledon.
b Tim Henmann hasn’t been winning the Wimbledon.

a Have you stopped eating?
b Have you been stopping eating?