Which one of the following compounds is an antifertility drug?

Drugs that regulate the female reproductive cycle and suppress either ovulation or implantation are called antifertility drugs. They are used in oral contraceptive pills.

Typical antifertility agents are synthetic steroidal preparations that mimic the natural hormones estrogen and progesterone, keeping their blood levels high so that ovulation does not occur.

Examples of popular formulations in India include Mala-D, Mala-N and, more recently, the non-steroidal weekly pill trademarked “Saheli” (generic name: CENTCHROMAN or ORMELOXIFENE). Saheli was developed by the CDRI, Lucknow, and is widely cited in NCERT texts as the standard example of an antifertility drug.

Among the given choices:
Aspirin - analgesic and antipyretic
Chloromycetin - broad-spectrum antibiotic (chloramphenicol)
Penicillin - antibiotic discovered by Alexander Fleming
Saheli - non-steroidal oral contraceptive (antifertility agent)

Therefore, the compound that acts as an antifertility drug is Saheli.

Option C which is: Saheli