For Each Bow the Romans Are Producing,they Give Up the Opportunity

For each bow the Romans are producing,they give up the opportunity to make 10 arrows.The Dacians are giving up producing 2 bows for every 40 arrows they are producing.Which of the following is true regarding opportunity cost?

A) The opportunity cost of producing arrows is lower for the Romans
B) The opportunity cost of producing arrows is higher for the Dacians
C) The opportunity cost of producing arrows is higher for the Romans
D) The opportunity cost of producing bows is identical for Dacians and Romans
E) The opportunity cost of producing bows cannot be calculated