The following transactions are the only ones made during the first 4 days of trading in a futures contract. DAY TRANSACTION A long 50, B short 50 A long 80, C short 80 A long 20, D short20 Clong 70, A sells 40, B sells 30 What is the open interest on these 4 days? 50, 130, 150, 180 50, 130, 150, 190 50, 130, 150, 110 50, 80, 20,70 None of the given answers are correct