The correct answer is (B) Force (implying exertion, vigor, and persistence); power; blow; stroke. Also, a mark or dent made by pressure, blow, exertion, etc.

Dint comes from Old English dynt (stroke, blow), Old Norse dynir.

Examples of use:

• He won a position on the team by dint of hard work.
• She wallpapered the rooms without help by dint of her perseverance.