Option 1 states that both the assertion (A) and the reason (R) are true, and that the reason is the correct explanation for the assertion. Let`s analyze each statement separately to determine their accuracy.

Assertion (A) states that the nucleus in plant cells is generally near the boundary wall. This statement is generally true. In plant cells, the nucleus is typically located near the periphery of the cell, close to the cell wall. However, it is important to note that the exact position of the nucleus can vary depending on the specific cell type and its function.

Reason (R) states that plant cells possess a single prominent vacuole occupying most of the volume of the cell. This statement is also true. Plant cells typically contain a large central vacuole that occupies a significant portion of the cell`s volume. The vacuole is involved in various functions, such as storing water, nutrients, and waste products.

The reason (R) provided does explain why the nucleus is generally near the boundary wall in plant cells. The presence of a large central vacuole limits the available space within the cell`s cytoplasm, pushing the nucleus towards the periphery of the cell.

Therefore, option 1 is correct as both the assertion and the reason are