An armored British carrier could defeat a Japanese carrier with guns

Could one aircraft carrier sink another with gunfire during Operation C?

Yes; if a British armored carrier reached gun range, its heavier armament and protection would make the encounter very dangerous for a Japanese carrier.

A carrier could sink another carrier with guns under the right circumstances. British armored carriers carried heavier protection and a stronger gun armament than their Japanese counterparts. Reaching gun range would remain the difficult step, but a night action during Operation C made the possibility more than a purely comic scenario. That possibility adds to the counterfactual case for a more aggressive Somerville response to Nagumo.