Given the equation:

You know that:
- The manufacturer has a total revenue given by this function:

Where "x" is the number of units that gives break-even for the product.
- The manufacturer has a total cost given by:

Therefore, knowing that:

You can set up this equation:

Now you can solve for "x":
- Apply the Subtraction Property of Equality by subtracting this term from both sides:

Then:


- Apply the Division Property of Equality by dividing both sides of the equation by 30:


Hence, the answer is: Option C.