[单选题]
Consider two pipes of the same le.ni zz t4so5r;ngth:42iqm bxh42ut one is open and the other is closed on one end. If the fundamental frequency of the open pipe is 300 Hz, what is the fundamental fqbt4m224 x uhirequency of the closed pipe?
A. $150 \; Hz$
B. $300 \; Hz$
C. $450 \; Hz$
D. $600 \; Hz$
