A portfolio's value is $80 million and its beta is 0.90. The current stock index futures price is 1,200 and the multiplier is $250. To increase the beta of the portfolio to 1.10, ______ stock index futures contracts, and to decrease the beta of the portfolio to 0.60, ______ stock index futures contracts.

a.buy 53, sell 80

b.buy 56, sell 80

c.sell 56, buy 90

d.sell 53, buy 90

e.sell 55, buy 100