Assertion : A narrow pulse of light is sent through a medium. The pulse will retain its shape as it travels through the medium. Reason : A narrow pulse is made of harmonic waves with a large range of wavelengths.

• A. If both assertion and reason are true and the reason is the correct explanation of the assertion.
• B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
• C. If assertion is true but reason is false.
• D. If the assertion and reason both are false.
• E. If assertion is false but reason is true.