Answer:
B. ) A pipe's length is equal to 1⁄2 of the wavelength of the sound waves produced by a tuning fork vibrating over one end of the pipe that's open to the air at both ends.
Step-by-step explanation:
Resonance is a phenomenon in which a vibrating body causes another body to vibrate at a specified frequency (or wavelength) with greater amplitude. Resonance also occurs in the following situations;
i. Swinging of a pendulum
ii. Plucking a string in an acoustic guitar
iii. Pushing of a playground swing at a regular interval