Select the word or phrase which best expresses the meaning of the word typed in bold: By his speech he fermented trouble in the ranks of the army.

Op 1: Quietened 
Op 2: Channelized into healthy directions 
Op 3: Stirred up 
Op 4: Contained and suppressed

Solution:

Option:3 (Stirred up)

incite or stir up (trouble or disorder).