Step 1: Know the structure.
The Code of Criminal Procedure, 1973 starts with definitions in Section 2. These define the key terms used in the Code.
Step 2: Understand a bailable offence.
A bailable offence is one where bail can be claimed as a matter of right once conditions are met.
Step 3: Find the exact clause.
Section 2(a) of the CrPC defines a bailable offence as one shown as bailable in the First Schedule or made bailable by any other law in force.
Step 4: See why it matters.
This classification decides the liberty of the accused and the powers of the police and courts on bail.
Step 5: Rule out wrong options.
Section 2(h), 2(x) and 2(c) define other terms, not a bailable offence. Only 2(a) fits.
Step 6: Final answer.
A bailable offence is defined in Section 2(a).
\[ \boxed{\text{Section 2(a)}} \]