If the total revenue curve of a firm is an upward sloping straight line, then which of the following is true for this firm?

Marginal revenue is always equal to average revenue.

The correct answer is Option (3) → Marginal revenue is always equal to average revenue.

If the Total Revenue (TR) curve is an upward-sloping straight line, it means revenue increases at a constant rate as output increases. The slope of the TR curve represents Marginal Revenue (MR), and since the slope is constant, MR is constant for every level of output.

In a perfectly competitive market, the firm sells each unit at the same price — therefore, MR=AR=Price.

Thus, when the total revenue curve is a straight upward-sloping line, Marginal Revenue is always equal to Average Revenue.