What will be the shape of unitary elastic supply curve?

Option 1 -> A 45° upward sloping line passing through the origin has unitary elasticity because the percentage change in quantity equals percentage change in price throughout.

Option 2 -> A straight line intercepting the X-axis has elasticity greater than 1 (elastic supply), not unitary elastic.

Option 3 -> Downward sloping lines represent demand curves or inverse relationships, not supply curves.

Option 4 -> Supply curves slope upward (positive relationship), not downward.

Hence, 45° upward sloping line -> For unitary elastic supply, the elasticity coefficient equals 1 throughout the curve. A straight line passing through the origin at 45° angle ensures that at every point, the ratio of percentage change in quantity to percentage change in price remains constant at 1. The 45° angle means the slope is 1, and since it passes through origin, P/Q ratio maintains unitary elasticity (Es = 1) at all points. -> correct