某投资者以2100元／吨卖出5月大豆期货合约一张，同时以2000元／吨买入7月大豆合约一张，当5月合约和7月合约价差为（）元／吨时，该投资人获利。

A.150

B.50

C.100

D.-80

Most Brazilians get along well with each other, _________ they are from different races(种族), including Americans, European settlers, and Africans,.

A．although

B．as a result

C．since

D．unless