As soon as they (1)/ entered the temple (2)/ they prayed to the gods on bent knees. (3)/ No error (4)

Answer

3

Explanation

on bended knee (s) (Id.) = if you ask for some thing on bended knee(s), you ask for it in a very hum ble/anxious way. Hence, they prayed to god(s) on bended knee(s) is the right usage