Step-by-step explanation:
Consider the provided information.
Integers: Integers are the set of whole number and the negatives of the natural numbers, i.e, … ,-2, -1, 0, 1, 2,...
Rational number: A number  
is said to be rational, if it is in the form  
of p/q. Where p and q are integer and  
denominator is not equal to 0.The decimal expansion of rational numbers may terminate or become periodic. 
Irrational  
number: A number is irrational if it cannot  
be expressed be expressed by dividing two  
integers. The decimal expansion of  
Irrational numbers are neither terminate nor  
periodic.
Now consider the provided statement "Negative numbers are integers." 
The statement is incorrect as all negative numbers are not integers they might be rational number or irrational numbers.
For example: -2.5 is a negative number but it is not an integer. The number is a rational number.
Hence, her statement is incorrect. 
She can say that all negative whole numbers are integers.