Identify the parent carbon chain

The compound has a longest chain of 7 carbons, so the parent name begins with hept-.

Identify the functional groups and multiple bonds

From the structure/options, the molecule contains:

• one alcohol group: $-OH$
• one double bond: $C=C$
• one triple bond: $C\equiv C$

Hence the suffix must include ol, en, and yn.

Choose the principal functional group

The alcohol group has highest priority among these, so numbering must give the lowest possible locant to $-OH$.

In all options, the hydroxyl group is at carbon $4$, so this condition is satisfied either way.

Resolve numbering using multiple bonds

Since the hydroxyl locant is tied, we next minimize the locants of the multiple bonds.

Compare the two possible numberings:

• One direction gives:

  • double bond at $1$
  • triple bond at $6$
  • alcohol at $4$

  So locants: $(1,6,4)$

• Opposite direction gives:

  • double bond at $6$
  • triple bond at $1$
  • alcohol at $4$

  So locants: $(6,1,4)$

For enyne systems, when there is a choice, the set with the lowest locant at the first point of difference is preferred. Thus $(1,6,4)$ is preferred over $(6,1,4)$.

Therefore numbering should be:

• alkene at $1$
• alkyne at $6$
• alcohol at $4$

Write the IUPAC name

The correct format is: $\text{Hept-1-en-6-yn-4-ol}$

Check the options

• A: 4-Hydroxyhept-6-en-1-yne ❌ Older-style naming; also not preferred because alcohol should be suffix, not prefix.
• B: Hept-1-en-6-yn-4-ol ✅
• C: Hept-6-en-1-yn-4-ol ❌
• D: 4-Hydroxyhept-1-en-6-yne ❌

Comparison with stored correct answer

My derived answer is B, which matches the stored correct answer.