William Wang, FRM, entered into the long position of two wheat future contracts matured on June. Each contract is 15,000 pounds of wheat. The current futures price is 150 cents per pound. The initial margin was about $5,000 for each contract and the maintenance margin was $3,500 for each contract. Based on the information above, what price changes will lead to the margin call and under what circumstances can $2000 be withdrawn from the margin account by investors?
选项：

A:When the futures price is below 140 cents/pound, investors will receive margin call; when the futures price rises to 156.67 cents/pound, investors can withdraw $2000 margin.
B:When the futures price is above 130 cents/pound, investors will receive margin call; when the futures price rises to 156.67 cents/pound, investors can withdraw $2000 margin.
C:When the futures price is below 140 cents/pound, investors will receive margin call; when the futures price rises to 163.33 cents/pound, investors can withdraw $2000 margin.
D:When the futures price is above 130 cents/pound, investors will receive margin call; when the futures price rises to 163.33 cents/pound, investors can withdraw $2000 margin.