The factory was built in a secret place, around _____ were high mountains.

A. where        B. it               C. that            D. Which

. The factory was built in a secret place, around _____ were high mountains.

A. where        B. it               C. that            D. which

The factory was built in a secret place, around _____ were high mountains.

The factory was built in a secret place, around _____ were high mountains．

A．where             B．it            C．that           D．which