Option 1: Sagacious -> means wise or shrewd; relates to intelligence, not honor or disgrace.
Option 2: Obtuse -> means dull or slow to understand; doesn't relate to reputation or honor.
Option 3: Estimable -> means worthy of respect and admiration; directly opposite to disgraceful.
Option 4: Disreputable -> means having a bad reputation; actually similar in meaning to ignominious.
Hence, Option 3: Estimable -> "Ignominious" means deserving public disgrace or shame, while "estimable" means deserving respect and esteem, making them perfect antonyms -> correct