Factors of 50 are the numbers which on dividing 50 leave no remainder. 50 is a composite number, therefore, it has more than 2 factors.
We can get the factors of 50 by Prime Factorization. We can draw a factor tree to get the prime factors of 50 as shown below:
Therefore, the prime factors are:

Hence, the other factors are:

Therefore, the factors of 50, including 1 and 50, are:

The question asks to sum all the factors between 1 and 50. This means that 1 and 50 are not included in the sum.
Therefore, the sum will be:

The correct option is OPTION A.