Given that both average revenue (AR) and Marginal revenue (MR) curves are of straight-line shape, it can be shown that (MR) curve will cut the distance between AR curve and the Y-axis in the middle, in other words, when both AR and MR curves are straight lines, then if a perpendicular is drawn from a point on the AR curve to the F-axis, MR curve will cut this perpendicular at its middle point.

Explanation:

The MR (Marginal Revenue) curve represents the change in revenue that a firm receives from selling one additional unit of a product. It is derived from the demand curve and has a downward sloping shape.

When the MR curve cuts the horizontal line between the Y-axis and the demand curve, it divides it into two equal parts.

Reasoning:

1. The horizontal line between the Y-axis and the demand curve represents the quantity of the product being sold.
2. The MR curve shows the additional revenue earned from each unit of the product sold.
3. When the MR curve intersects the horizontal line, it indicates the quantity at which the additional revenue from selling an additional unit is equal to the price of the product.
4. At this point, the firm is maximizing its profit because it is selling the quantity of the product where the marginal cost equals the marginal revenue.
5. Since the MR curve is derived from the demand curve, the point where it intersects the horizontal line represents the equilibrium quantity of the product being sold.
6. This equilibrium quantity divides the horizontal line into two equal parts, as the MR curve represents the additional revenue from selling each unit of the product.
7. Therefore, the correct answer is option 'B' - the MR curve cuts the horizontal line between the Y-axis and the demand curve into two equal parts.

Summary:

The MR curve cuts the horizontal line between the Y-axis and the demand curve into two equal parts. This represents the equilibrium quantity of the product being sold, where the additional revenue from selling each unit is equal to the price of the product. The MR curve is derived from the demand curve and has a downward sloping shape.