Answer:
D. all of the above
Explanation:
Conifers are a group of trees which belong to the class of gymnosperms. They are cone bearing plants which means that the seeds are formed in a beautiful cone shaped structure. Some of the trees belonging to this class are shrubs while majority of them are trees.
Some significant features of the leaves of conifers are those mentioned in the question. They have a very heavy cuticle in the region of epidermis for protection of leaves. The stomata are deeply sunken in leaves and are present in the form of layers. Moreover, the leaves are very thin like those of grasses and therefore they have very less surface area as compared to the leaves of other plants like roses.
Please see the conifer leaves in attached picture for better understanding.