This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to prune rosa rugosa
Know when to prune.
Most pruning should be done once the plant enters its dormant season. This can be any point in time between late autumn and early spring.

Pick from:
a). Stop pruning in late summer or early fall and reprune in mid-spring. If you are still growing rosa rugosa, the pruning will probably be at its peak in the late spring, just before the sun sets..
b). Pruning anywhere outside of the dormant season can impact the plant's overall health and affect its flowers. The best time to prune rosa rugosa for the first time is when it is dormant with no rain falling..
c). Trim down the plant with an inter-growth cane or try trimming down the foliage. Prune large, bushy canes if possible..
d). The best time to prune is in the early spring, after the danger of frost has passed. Pruning makes a plant vulnerable, and vulnerable plants tend to be weaker against the cold frosts of winter..
The answer is:
d).