Given that there are 120 employees.

m% are male, so (100-m)% are female.

Also, c% are custodians.

Let x MALE members and y FEMALE members be custodians.

So, x + y = c%

1) Using the first condition, we know that m + c = 50

m can take values from 0 to 50 and so there is no UNIQUE value of m. This implies there is no unique value c as well as f.

Since we don't have unique values, we cannot determine the required number of females.

2) Using the second condition, we know that female who are custodians are 4.

So, y = 4

But we don't know what x is. Hence we cannot know c.

So this condition also cannot give us an answer.

3) Using BOTH the conditions, we know that m + c = 50 and y = 4.

Once again, we cannot find x and hence we cannot find c.

So using both the conditions as well, we cannot identify the answer.

Hence (E).

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