From the following statements about a firm's supply curve, select the correct statements:

(A) Technological progress is expected to shift the supply curve of a firm to the right.
(B) An increase in input prices is expected to shift the supply curve of a firm to the left.
(C) A decrease in input prices is expected to shift the supply curve of a firm to the left.
(D) The imposition of a unit tax shifts the supply curve of a firm to the left.

Choose the correct answer from the options given below:

(A), (B) and (D) only

The correct answer is Option (1) → (A), (B) and (D) only

• (A) Technological progress is expected to shift the supply curve of a firm to the right. Correct. Technological progress lowers the cost of production, allowing the firm to produce more at the same price. This is an increase in supply, or a rightward shift.

• (B) An increase in input prices is expected to shift the supply curve of a firm to the left. Correct. Higher input prices (like wages or raw materials) increase the cost of production, causing the firm to supply less at the same price. This is a decrease in supply, or a leftward shift.

• (C) A decrease in input prices is expected to shift the supply curve of a firm to the left. Incorrect. A decrease in input prices lowers the cost of production, which would cause the supply curve to shift to the right (an increase in supply).

• (D) The imposition of a unit tax shifts the supply curve of a firm to the left. Correct. A unit tax is an additional cost for every unit produced, which increases the firm's marginal cost. This decreases the supply, or shifts the supply curve to the left.