It would be nice to know some options, but here's Morris's speed.
Since Morris is traveling at three feet per second, we want to change it to per hour.
3 * 3600 = 10800 feet per hour
And we would want to convert that to miles per hour.
10800/5280 is about 2, more specifically 2.05 ish.
So Morris is traveling 2 mph less then 50, or about 48 mph.
ANSWER
D) sin Y
EXPLANATION
The given triangle is a right triangle.
This implies that that:

Then we have

Recall that

But

When we do the substitution, we get,

Therefore cos(x) is a equivalent to sin(y).
The correct answer is D.
X is equal to 5 because 2x+4=14