Torpedo or directly placed contact charge... Getting that precise placement with a static mine is highly unlikely (more like pure, rotten luck...).
This was a controlled and deliberate attack.
I’d use a single torpedo, passively guided with no active sonar = no warning except the “swish” of the torpedo screws.
Noisiest, most vulnerable part of the ship is the engine room = best target for a torpedo homing in on a noise source.
Alt? Lay a mine with a torpedo attached. Program it as follows: “At noise level xxx decibels, Doppler increasing (range closing), launch torpedo towards noise. After launch, open air flotation valve.” With no buoyancy, the launching mine and its anchor sinks to bottom, giving no trace for the attacked Navy to locate except by a long and expensive and probably unsuccessful sonar search.