The correct option is C either a proper or an improper fraction
The denominator is always greater than the numerator of a proper fraction. So, value of a proper fraction lies between 0 and 1.
If two given proper fractions are lesser than 12, then the summation will be less than 1, and it will be a proper fraction.
If two given proper fractions are greater than 12, then the summation will be greater than 1, and it will be an improper fraction.
Hence, the addition of two proper fractions will always be either a proper or an improper fraction.