单项选择题

GB/T699-1999《优质碳素结构钢》中规定:优质钢的S、P含量为()

A.S≤0.030% P≤0.030%
B.S≤0.030% P≤0.035%
C.S≤0.035% P≤0.030%
D.S≤0.035% P≤0.035%