Step 1: Cut the product in two:
Draw 3,4-diethyl-3,4-dimethylhexane. The two quaternary carbons C3 and C4 are joined to each other. Each also bears a methyl, an ethyl branch and a chain end that is an ethyl.
Step 2: Name the fragment:
Each fragment is a carbon with substituents $-\text{CH}_3$, $-\text{C}_2\text{H}_5$, $-\text{C}_2\text{H}_5$. The parent is pentane with the carbon in the middle, position 3, so the fragment is a 3-methylpentan-3-yl group.
Step 3: Add the halogen:
The tertiary chloride is $\text{(C}_2\text{H}_5)_2\text{C(CH}_3)\text{Cl}$, which is 3-chloro-3-methylpentane. Sodium in dry ether couples two of these to give the required product.
Options (A), (B) and (D) have the chlorine on C2 or C3 of a different skeleton and would couple to other alkanes.
Final Answer:
Option (C).
\[ \boxed{\text{3-chloro-3-methylpentane (C)}} \]