Late in the night you happen to hear strange sounds from the house of your immediate neighbour. You…

The correct choice is: go to your neighbour and enquire whether he needs help

A good neighbour shows concern: check whether the neighbour is in difficulty and offer help (calling the police if it turns out to be needed).

Ignoring it is uncaring, and calling the police or waking everyone before knowing what happened may be an over-reaction.

Hence the answer is ‘go to your neighbour and enquire whether he needs help’.