The correct option is B.
If a number n is multiply by a number than lies between 0 to 1, then the product is less than the initial number.
If a number n is multiply by a number that is greater than 1, then the product is greater than the initial number.
It is given that Fiona multiplies a number by 2/3.The product is greater than 2/3. It means the number which is multiplies by Fiona is must be greater than 1.
That number is . Therefore the correct option is B.