C)
1) Examining those sentences we have:
A) Integers and fractions are rational numbers. True
Since any integer is a Rational number and fractions are ratios.
B) Whole numbers are rational numbers. True
The whole Number Set is within at Rational Set
C) π is a rational number. False
π is an Irrational number for can't be written as a ratio a/b.
D) square root of 25 is a rational number. True
Since √25 = 5 and 5 is a rational number.