આપેલ વાક્ય $Active$ (કર્તરી) પ્રયોગમાં છે. આપેલા વિકલ્પોમાંથી સાચું $Passive$ (કર્મણી) પ્રયોગનું રૂપ પસંદ કરો: "They have built a perfect dam across the river."

• A
  Across the river a perfect dam was built.
• B
  $A$ perfect dam has been built by them across the river.
• C
  $A$ perfect dam should have been built by them.
• D
  Across the river was a perfect dam.