The following transactions are the only ones made during the first 4 days that a futures contract trades.

DAY TRANSACTION

1 A long 30, B short 30

2 A long 55, C short 55

3 A long 45, D short 45 4

C long 45, A sells 20, B sells 25

What is the open interest on these days?

30, 85, 130, 110

30, 85, 130, 115

30, 85, 130, 105

30, 55, 45, 50