Hysterosalpingography (HSG) is best performed on which day of the menstrual cycle?

Correct option is C

HSG is ideally done on Day 8–10, after menstruation ends but before ovulation → reduces infection risk and avoids disrupting early pregnancy.
Explanation of options: (a) ✘ Too early, menstruation ongoing. (b) ✘ 5–7 is still near menstruation end, risk of contamination. (c) ✔ Correct; Day 8–10 = safest window. (d) ✘ 18–20 = post-ovulation, pregnancy risk.