**Concept: The question tests on the area of Arithmetic(DS).**

**Solution:**

Let the number of individual memberships = x. Then the number of partner memberships = 3x.

Also let the cost of each partner membership = y

Then Total Revenue = 375x + 3xy = x (375 + 3y)**Statement 1:** The cost of each partner membership was $500.

This gives us the value of y, but we do not have information on the number of individual or partnership members.

Therefore Statement 1 Alone is Insufficient. Answer options could be B, C or E.**(Insufficient)****Statement 2:** The revenue from individual memberships was 1/5 of the total revenue from all memberships

375x = 1/5 * (375x + 3xy)

5 * 375x = 375x + 3xy

4 * 375x = 3xy

y = 4 * 125 = 500

Again from this statement, we do not get any information on the number of individual or partnership members.

Therefore Statement 2 Alone is Insufficient. Answer Options could be C or E.**(Insufficient)****Combining Both Statements: **

We get the same information for y from both the statements as shown.

Therefore Both Statements together are Insufficient.

**(Option e)**