Let's analyse each option:
1.The denominator cannot be the same as one of the factors
False, the denominator can be the same, as in this example:
2.The answer cannot be an improper fraction
False, there is no problem in the answer being an improper fraction, as in the example above.
3.The answer must be less than 7/8
False, the answer would be less than 7/8 if the second number was lesser than 1.
4. 7/8 of a number cannot be greater than the number
True. The number 7/8 is lesser than 1, so its product with another number must be lesser than the second number. And Anna's answer (7/2) is bigger than the