4. What is the name for the following? A) hexane B) dimethylbutane C) 3,3-dimethylbutane D) 2,2-dimethylbutane E) 2-dimethylbutane 5. What is the IUPAC name of this alkane? A) 4-ethyl-2,2-dimethylpentane B) 2-ethyl-4,4-dimethylpentane C) 2,2,4-trimethylhexane D) 2-ethyl-2,2-dimethylpentane E) 3,5,5-trimethylhexane 6. Which of the following compounds could have the molecular formula \( \mathrm{C}_{7} \mathrm{H}_{16} \) ? A) hexane B) pentane C) 2-methylheptane D) 2,3-dimethylpentane E) 3-methylhexane F) Both D and E