Frank is looking for his girlfriend in a large crowd of people. Because he is so focused on finding her, he fails to notice when a man in a clown costume walks by, despite looking directly at him. This is an example of:

a. a feature detection failure.

b. sensory overload.

c. sensory adaptation.

d. inattentional blindness.

D

Explanation:

"Also known as perceptual blindness, inattentive blindness results from a lack of attention that is not associated with vision defects or deficits, as an individual fails to perceive an unexpected stimulus in plain sight."- google

Basically when a person is focused on a task they unintentionally fail to notice other things.  

The answer is C. Frequency.

Explanation:

The equation for speed of a wave is calculated by multiplying the "frequency" (1 wavelength divided by 1 second) of a wave by its wavelength.

Equation is Speed= frequency(hertz) x wavelength (meters).

version 2 is wavelength/time x distance/wavelength= distance/time.