The correct answer is (C) To interlock (as with gear teeth); to become interlocked or cause to become interlocked; to be engaged (with others); to catch or entangle in, or as if in, a net; to enmesh. Also, to co-ordinate, combine, or match. To be harmonious.

Mesh comes from Old English mæscre (mesh).

Examples of use:

• The husband and wife were able to mesh their schedules successfully.
• The enthusiasm and skills of the two pianists meshed to produce a highly entertaining duet.