Explanation:
2,3-diethyl hexane
At first we select a long chain.
Then, we number that chain from that side where substituent position is closer.
Then, we write it's IUPAC name
Position of substituent + substituent name + chain name + suffix
Here,
2,3 + -diethyl + hex + -ane
= 2,3-diethyl hexane
Answer: A. It indicates the direction in which the reaction occurs.
