Looking for answers? Westonci.ca is your go-to Q&A platform, offering quick, trustworthy responses from a community of experts. Get immediate and reliable solutions to your questions from a knowledgeable community of professionals on our platform. Discover detailed answers to your questions from a wide network of experts on our comprehensive Q&A platform.

Which of the following describes the sound you hear as an emergency vehicle's siren comes towards you?
a. The pitch increases.
b. The pitch is the same as the one emitted from a non-moving vehicle.
c. The pitch diminishes completely.
d. The pitch decreases.