A unifoliate compound leaf can be differentiated from simple leaf in having 

Concept: The leaves of a plant can be divided into two categories: simple leaves and compound leaves. The compound leaves can be further classified into pinnate and palmate leaves. 

In the case of a palmate compound leaf, the leaflet emerges from the tip of the petiole. Depending on the number of leaflets that emerge from the petiole, the leaf can be differentiated into unifoliate, bifoliate and so on. The difference between a unifoliate compound leaf and a simple leaf is that the unifoliate compound leaf possesses a winged or a jointed petiole. 

Hence, the correct answer is option A.