In the context of abstract-syntax-tree (AST) and control-flow-graph (CFG), which one of the following is TRUE?

Let us analyze the given statements regarding AST and CFG:

• Option A is False: In a CFG, backward edges (such as in loops or backwards goto jumps) can lead from a node $N_1$ to a successor $N_2$ whose corresponding code appears earlier in the program text.

• Option B is False: A CFG will contain cycles whenever the input program contains loops or recursive flow constructs.

• Option C: The number of successors of a node in an AST depends on the construct (for instance, an $n$-ary operator or a statement list) and in a CFG depends on branching constructs (such as a multi-way switch statement), which vary with the input program. However, under certain restricted standard definitions of AST/CFG, this phrasing was deemed ambiguous, and this question was marked as Marks to All (MTA) in the official GATE key.

• Option D is False: A basic block in a CFG typically comprises a sequence of multiple consecutive three-address code statements, not at most one.