Step 1: Understanding the phenol.
2, 5-dichlorophenol is isolated from the defensive secretion of certain grasshopper species. It is a defensive chemical that helps to protect the grasshopper from predators.
Step 2: Analyzing the options.
(A) 4-Methylphenol: This is not the correct phenol isolated from grasshopper secretion.
(B) Benzene-1, 3-diol: Incorrect — This is a different compound.
(C) 2, 5-dichlorophenol: Correct — This is the correct phenol isolated from grasshopper secretion.
(D) Phenol: Incorrect — This is a simple phenol, not the one isolated in this case.
Step 3: Conclusion.
The correct answer is (C) 2, 5-dichlorophenol, as it is isolated from the defensive secretion of grasshoppers.