The correct option is D height of the tree
Size of the garden represents the area as it is the amount of space covered by a shape.
Width of the whiteboard represents the length as here it is telling how wide (long) the Whiteboard is.
Capacity of fuel tank represents the volume as it is the amount of space occupied by the object.
Height of the tree represents the length it is telling how tall (long) the tree is.
Hence, options (b.) and (d.) are correct options.