The answer to your question would be "B"
1.425
Rational numbers are numbers that can be turned into a fraction. Decimals, fractions, and integers are rational numbers.
"A" would be incorrect because there is no way to write
as a simple fraction.
"C" would be incorrect because the square root of 50 is not a perfect square.
"D" would also be incorrect because it can not be turned into a fraction.