Step 1: Understand the question.
The Code of Criminal Procedure, 1973 starts with a definitions section, which is Section 2. The question asks which exact sub-clause of Section 2 defines a bailable offence.
Step 2: Know what bailable offence means.
A bailable offence is one where the accused has a right to be released on bail. The Code tells us where to find this definition.
Step 3: Recall the correct sub-clause.
Section 2(a) of the CrPC defines a bailable offence as an offence shown as bailable in the First Schedule, or made bailable by any other law in force.
Step 4: Compare with nearby clauses.
Section 2(c) defines a cognizable offence, and the other sub-clauses define different terms. So they are not the right place for bailable offence.
Step 5: Match to the option.
Among the options, the one that says Section 2(a) is the correct definition clause for a bailable offence.
Step 6: State the answer.
So the bailable offence is defined under Section 2(a). \[ \boxed{\text{Section 2(a)}} \]