Carcass wrote:
By (i) ________ strict rules of hygiene in maternity wards, Ignaz Semmelweis saved many women from dying of childbed fever, a fate that many expectant mothers feared.
| Blank (i) |
| (A) chellenging |
| (B) instituting |
| (C) intimating |
| (D) invalidating |
| (E) sanitizing |
Ignaz saves life, so something new has come to change something that was a reason of deaths earlier. This is also further substantiated by the words ' a date that expectant mothers feared'..
Something which was not there has been started, and that is the 'hygiene rules'
INSTITUTING is the closest in meaning of starting something new..
B