Step 1: Understanding the compound.
Petrol (gasoline) is a hydrocarbon compound that typically contains carbon atoms in the range of C\(_6\) to C\(_7\), which makes it the correct answer.
Step 2: Analyzing the options.
(A) Waxes: Waxes generally contain longer carbon chains, more than C\(_7\).
(B) Petrol: Correct — Petrol is a mixture of hydrocarbons with carbon atoms in the range of C\(_6\) to C\(_7\).
(C) Diesel: Diesel fuel contains hydrocarbons in a slightly higher range, typically C\(_8\) to C\(_20\).
(D) CNG: CNG (compressed natural gas) mainly contains methane (CH\(_4\)), with smaller carbon numbers.
Step 3: Conclusion.
The correct answer is (B) Petrol.