The simplified ratio is 1 ft : 14 ft.
To simplify the given ratio of 15 feet to 210 feet, you need to find the greatest common divisor (GCD) of the two numbers and then divide both by the GCD.
The GCD of 15 and 210 is 15.
Divide both numbers by the GCD:
15 ÷ 15 = 1
210 ÷ 15 = 14
So, the simplified ratio is 1 ft : 14 ft. The correct answer is the first option.