What should be the size of a planting pit in relation to the root ball?

The appropriate size of a planting pit should be five times the width of the root ball, which allows for adequate room for root development and growth. This larger pit size facilitates the penetration of roots into the surrounding soil, encouraging healthy establishment and reducing transplant shock.

Having a planting pit that exceeds the root ball's width significantly benefits the plant by providing loose, well-aerated soil that can hold moisture and nutrients while also stimulating root expansion in the new environment. A pit that is too small might restrict root growth and lead to issues such as girdling roots or poor water and nutrient uptake, ultimately affecting the plant's health.

While the other options present alternative sizing methods, they do not provide the optimal conditions for root development that a five-times-the-width pit offers. Therefore, the choice of five times the width aligns with proper horticultural practices for transplanting to ensure a successful and healthy establishment of the plant.