[单选题]
A 3.00-m long pipe is i +i-mu5( hjd5f)cdto qn a n1lc+66ed pk/oe,db:g3lkw 0k hd3 ieroom where the temperature is $20 \; ^{\circ}C$. What is the fundamental frequency if the pipe is closed at one end?
A. $57 \; Hz$
B. $114 \; Hz$
C. $29 \; Hz$
D. none of the above
