Hint: Transfusion tissues are found around the vascular bundles of the gymnosperms and in particular where is what you need to crack.
First of all, you should know what transfusion tissue is. Transfusion tissue is the tissue which is found around the vascular bundles of gymnosperms leaves. These are helpful for conduction of water in the leaflets of Cycas and Pinus. Like the living cells of parenchyma with walls, it also consists of both living cells which are non-lignified and lignified tracheids with bordered pits. Transfusion tissue is composed of three types of cells- tracheids, parenchyma and albuminous cells.
Now we know that these are found in the leaves so we can look at the options.
> Option A is Cycas (leaflet) This is the correct option as transfusion tissue is found around the vascular bundles in the leaflet of Cycas and Pinus.
> Option B is ginkgo (stem) and this option is incorrect as these tissues are not found in stems.
> Option C is Pinus(root), this option is also incorrect because the transfusion tissue is found in Pinus but not in the roots of Pinus but these are found in the leaflets of Pinus. So this option gets eliminated.
> Last option is Both A and C, this cannot be the right one since option A is correct but option C is not the correct one therefore this is not the correct one.
Hence, The correct answer is option (A).
The main function of the transfusion tissue is to transport the material between vascular bundles and the mesophyll. The phylogenetic relationship of various taxa of gymnosperms is discussed on the basis of the three different kinds of transfusion tissues which are thick-walled tracheids, parenchyma and albuminous cells.
Note: Transfusion tissue is found around the vascular bundles in the leaflets of Pinus and Cycas therefore from the given options it is clear that in the first option only leaflet is given and that too of Cycas so this is the correct one. Also, if you know these are found in the leaflets then you can't go wrong with this question.