The correct answer is option 'A': The main function of a municipal corporation is not to look after the needs of the farmers.

Explanation:
A municipal corporation is a local governing body that is responsible for the administration of urban areas. It is primarily concerned with providing public services and maintaining the infrastructure of the city or town. While the needs of farmers are important, they fall under the jurisdiction of agricultural departments, not municipal corporations.

Let's discuss each option in detail:

a) The main function of a municipal corporation is to look after the needs of the farmers:
This statement is false. The main function of a municipal corporation is to provide basic civic amenities and services to the residents of the city or town. Some of the key functions of a municipal corporation include:

- Maintaining public health and sanitation
- Providing clean drinking water supply
- Ensuring proper waste management and disposal
- Constructing and maintaining roads, bridges, and other infrastructure
- Managing public transportation
- Monitoring and regulating urban planning and development
- Collecting property taxes and other fees for revenue generation

b) The minimum age of a voter in municipal elections is 18 years:
This statement is true. In most democratic countries, including India, the minimum age for voting in municipal elections is 18 years. This is consistent with the minimum voting age for other elections such as state and national elections.

c) The health officer is an important permanent officer of a municipality:
This statement is true. The health officer is an important permanent officer of a municipality. The health officer is responsible for overseeing public health initiatives, ensuring sanitation and cleanliness, and preventing the outbreak and spread of diseases within the jurisdiction of the municipality.

d) Tax on houses and land is one of the main sources of the income of the municipality:
This statement is true. Tax on houses and land is one of the primary sources of income for a municipality. Property taxes are levied on residential, commercial, and industrial properties within the municipal area. This revenue is essential for the municipality to fund its various functions and provide services to the residents.

In conclusion, option 'A' is false because the main function of a municipal corporation is not to look after the needs of the farmers. Instead, it is responsible for providing essential public services and maintaining the infrastructure of the city or town.