Question

click on the wave that has the larger wavelength.
simulations used in this interactive are by phet interactive simulations
university of colorado boulder, licensed under cc - by - 4.0 (https://phet.colorado.edu).

Explanation:

Wavelength is the distance between two consecutive crests (or troughs) of a wave. Looking at the two waves, wave B has fewer crests in the given space compared to wave A. Fewer crests mean a larger distance between them, which implies a larger wavelength.

Answer:

B.