Identify the substrate in the following reaction: A substrate with SMILES string CCCCCC(C)Br reacts with N a C N in the presence of D M S O to yield SMILES string CCCCCC(C)[CN]. Which of the following is the substrate?
1) 2-bromoheptane
2) Na⁺
3) N≡ C-
4) Br-
5) DMSO