Assertion: When supply of a commodity changes due to change in its own price it is called as change in supply.

Reasoning: When there is increase in supply, the supply curve shifts leftwards and when there is decrease in supply, the supply curve shifts rightwards.

Both Assertion (A) and Reasoning (R) are not correct.

The correct answer is Option 3: Both Assertion (A) and Reasoning (R) are not correct.

Assertion: "When supply of a commodity changes due to change in its own price it is called as change in supply."This is incorrect. When the supply changes due to a change in the product's own price, it's called a "change in quantity supplied," not "change in supply." "Change in supply" refers to shifts of the supply curve caused by factors other than the product's price.

Reasoning: "When there is increase in supply, the supply curve shifts leftwards and when there is decrease in supply, the supply curve shifts rightwards."This is also incorrect. An increase in supply is represented by a shift of the supply curve to the right. A decrease in supply is represented by a shift of the supply curve to the left.