Correct Answer: Both assertion and reason are true, and the reason is the correct explanation of the assertion.

Solution : The correct answer is (a) Both assertion and reason are true, and the reason is the correct explanation of the assertion.

The assertion states that structural unemployment occurs due to a mismatch of skills between job seekers and available jobs, which is true. Structural unemployment is a type of unemployment that arises when there is a fundamental mismatch between the skills possessed by job seekers and the skills required for available jobs. This mismatch can occur due to various factors such as changes in technology, shifts in the economy, or changes in the demand for certain skills.

The reason provided supports the assertion by stating that technological advancements and changes in the economy require new skill sets. As technology evolves and the economy undergoes changes, the demand for certain skills may decrease while the demand for new or different skills may increase. This can result in a situation where job seekers may not possess the required skills for the available jobs, leading to structural unemployment.

Therefore, both the assertion and reason are true, and the reason correctly explains the assertion.