While building tunnel through the mountins, ______.n underground lke ws discovered B．there

wWhile building tunnel through the mountins, ______.n underground lke ws discovered B．there wsn underground lke discovered C． lke ws discovered underground D．the workers discoveredn underground lkeA．an underground lake was discoveredB．there was an underground lake discoveredC．a lake was discovered undergrounD．the workers discovered an underground lake