They ___ all the window panes.

This question tests knowledge of correct verb forms and appropriate vocabulary in context. The action described is the damaging of window panes. The past tense of the verb "to break" is needed here.

• Broke is correct because it is the past tense of "break," meaning to shatter or damage, which accurately describes what happened to the window panes.
• "Rowed" is incorrect; it is the past tense of "row" (to propel a boat or arrange in a line), which is irrelevant to window panes.
• "Pealed" is incorrect; it is the past tense of "peal" (to ring loudly, like bells), which does not fit the context.
• "Has cut" is grammatically incorrect with the plural subject "They" (it should be "have cut") and "cut" does not typically convey the shattering of window panes as effectively as "broke."