The CrPC's definitions section assigns a specific letter to each defined term, so identifying "bailable offence" is really about matching the right letter to the right concept.
Since only one lettered clause is tied to the concept of bail eligibility, the answer follows directly from the structure of Section 2.
\[ \boxed{\text{Section 2(a)}} \]Since all four options point to different sub-clauses of the same definitions section, the safest approach is to recall what each specific letter defines rather than guess.
Distinguishing the bail-related definition from its closely related neighbour, cognizable offence, isolates the correct sub-clause.
Hence, the correct answer is Section 2(a).