Explanation:

All pairs are correctly matched.

• Unemployment occurs when a person who is actively searching for employment is unable to find work.

Types of Unemployment in India
Disguised Unemployment: It is a phenomenon wherein more people are employed than actually needed.

• It is primarily traced in the agricultural and the unorganised sectors of India.

1st is correct: Seasonal Unemployment: It is an unemployment that occurs during certain seasons of the year.

• Agricultural labourers in India rarely have work throughout the year.

2nd is correct: Structural Unemployment: It is a category of unemployment arising from the mismatch between the jobs available in the market and the skills of the available workers in the market.

• Many people in India do not get jobs due to lack of requisite skills and due to poor education level, it becomes difficult to train them.

Cyclical Unemployment: It is a result of the business cycle, where unemployment rises during recessions and declines with economic growth.

• Cyclical unemployment figures in India are negligible. It is a phenomenon that is mostly found in capitalist economies.

Technological Unemployment: It is the loss of jobs due to changes in technology.

• In 2016, World Bank data predicted that the proportion of jobs threatened by automation in India is 69% year-on-year.

3rd is correct: Frictional Unemployment: The Frictional Unemployment also called as Search Unemployment, refers to the time lag between the jobs when an individual is searching for a new job or is switching between the jobs.

• In other words, an employee requires time for searching a new job or shifting from the existing to a new job, this inevitable time delay causes frictional unemployment.
• It is often considered as voluntary unemployment because it is not caused due to the shortage of job, but in fact, the workers themselves quit their jobs in search of better opportunities.

4th is correct: Vulnerable Employment: This means, people working informally, without proper job contracts and thus sans any legal protection.

• These persons are deemed ‘unemployed’ since records of their work are never maintained.
• It is one of the main types of unemployment in India.

Hence option 4th is correct.