The correct answer is option 'D', which is 17.5%.

Agriculture is one of the key sectors of any economy, and its contribution to the Gross National Product (GNP) is a significant indicator of economic growth and development. The GNP measures the total value of all goods and services produced by a country's residents, both domestically and abroad, in a specific period.

Here are the key points explaining why the contribution of agriculture to GNP is approximately 17.5%:

1. Importance of Agriculture:
- Agriculture plays a crucial role in providing food, raw materials, and employment opportunities to a significant portion of the population.
- It contributes to the overall economic development by providing inputs to other sectors such as manufacturing and services.

2. Calculation of Contribution to GNP:
- The contribution of agriculture to GNP is determined by comparing the value of agricultural production to the total value of all goods and services produced in the country.
- The ratio of agricultural value-added to GNP is expressed as a percentage to understand its relative significance.

3. Factors Affecting the Contribution:
- The contribution of agriculture to GNP can vary from country to country and over time due to various factors:
a) Economic Structure: Countries with a larger agricultural sector tend to have a higher contribution to GNP from agriculture.
b) Technological Advancements: The adoption of modern farming techniques and technologies can increase agricultural productivity and its contribution to GNP.
c) Government Policies: Government policies related to agricultural subsidies, trade restrictions, and investment in rural infrastructure can have a significant impact on the contribution of agriculture to GNP.

4. Global and Regional Variations:
- The contribution of agriculture to GNP can vary significantly across countries and regions.
- In developed countries with diversified economies, the contribution of agriculture to GNP may be relatively lower compared to developing countries where agriculture is a dominant sector.
- However, even in developed countries, agriculture remains an essential sector and contributes significantly to the overall economy.

In conclusion, the contribution of agriculture to Gross National Product is approximately 17.5%. This percentage reflects the value of agricultural production in relation to the total value of goods and services produced in the country. Agriculture's contribution to GNP can vary based on economic structure, technological advancements, and government policies. Regardless of the variations, agriculture remains a crucial sector for food security, employment, and overall economic development.