Answer:
A. 2,3-dimethylhexane
Explanation:
To determine what is the molecule shown, you need to: identify radical groups and count the carbons.
The numbers at the beginning of the name point where the methyl groups are located, so in the second and third carbon from left to right (therefore, 2,3), and since we have two, it is dimethyl. The term "hexane" is the number of carbons that compose the very core of the molecule.
In the image below, the molecule of 2,3-dimethylhexane is mirrored, but as you can see, there is methyl on the second and third carbon from right to left. An observation: this image and the molecule in the question are not enantiomers.
Why not the others?
B. 2-penthylpropane points out that there is a Penthyl group in the second carbon from left to right or right to left, and that there are 5 core carbons in the structure, instead of six.
C. 4-propylpentane points out that there is a Propyl group in the second carbon from left to right or right to left, and that there are 5 core carbons in the structure, instead of six.
D. Octane ignores the existence of the two methyl groups present on the structure, so it is also the wrong one.
