Which of the following is not a type of tide?
a. low tide
c. fall tide
b. high tide
d. spring tide

fall tide  

Explanation:

Due to combined effect of gravitational force of the sun and the moon, the sea level rises and falls. These are known as tides.

High tide is when the sea level rises. Low tide refers to the decrease in the sea level.

Spring tide occurs when the difference between high tide and low tide is maximum. This happens when the gravitational pull of  the sun and the moon is strongest - when the sun, earth and moon are aligned in a straight line (during full moon and new moon).

Neap tides occur when the difference between the high tides and low tides is minimum. This occurs when the sun, moon and earth are aligned at right angle.

Fall tide is not a type of tide.

the answer would be 32*f