Final answer:
Marie Stopes was the woman who set up a free birth control clinic in Holloway in 1920 and was a family planning pioneer.
Step-by-step explanation:
The woman who set up a free birth control clinic in Holloway in 1920 was Marie Stopes.
She was a British author and paleobotanist who made significant contributions to science and was the first woman on the faculty of the University of Manchester.
Stopes was also a family planning pioneer and advocated for the use of contraception.