The set of full binary trees is defined as follows Basis: A single vertex with no edges is a full binary tree. The root is the only vertex in the tree. Recursive rule: If T1 and T2 are full binary trees, then a new tree T' can be constructed by first placing T1 to the left of T2, adding a new vertex v at the top and then adding an edge between v and the root of T1 and an edge between v and the root of T2. The new vertex v is the root of T'. Suppose that a full binary tree T' is created using the recursive rule applied to full binary trees T1 and T2. Let v(T) denote the number of vertices in tree T. Which expression correctly describes v(T")?
a. v( T') =v( Tl) + v( T2) + 1
b. v( T') =2v( Tl) + 2v( T2) + 1
c. v( T') =v( Tl) 2v( T2)
d. v( T') = 2v( Tl) + 2v( T2)