Mesh analysis is a powerful technique used in electrical circuit analysis to determine the currents flowing in different branches of a circuit. It is particularly useful for analyzing planar circuits, which are circuits that can be drawn on a plane without any branches crossing over each other.

Planar circuits are commonly encountered in electrical engineering, as they represent many practical circuit configurations such as series and parallel combinations of resistors, capacitors, and inductors. Mesh analysis is based on Kirchhoff's voltage law (KVL), which states that the sum of the voltages around any closed loop in a circuit is equal to zero. By applying KVL to each mesh, or closed loop, in a planar circuit, we can derive a set of simultaneous equations that can be solved to find the unknown currents.

Here are the main reasons why mesh analysis is suitable for planar circuits:

1. Meshes: In mesh analysis, the circuit is divided into meshes, which are closed loops that do not contain any other loops within them. Planar circuits can be easily divided into non-overlapping meshes, making it easier to apply mesh analysis.

2. Current Sources: Planar circuits often contain current sources, which are elements that provide a known current. Mesh analysis allows us to directly incorporate these current sources into the mesh equations, simplifying the analysis.

3. Voltage Sources: Planar circuits may also include voltage sources, which are elements that provide a known voltage. Since voltage sources can be represented as an ideal voltage source in series with an internal resistance, they can be easily incorporated into the mesh equations.

4. Simplicity: Mesh analysis is a systematic and straightforward method for solving planar circuits. By applying KVL to each mesh, we can derive a set of equations that can be solved using various techniques, such as matrix methods or substitution.

In summary, mesh analysis is a powerful tool for analyzing planar circuits because it allows us to apply Kirchhoff's voltage law to each mesh in the circuit, derive a set of equations, and solve for the unknown currents. It is particularly suitable for planar circuits due to their inherent characteristics and simplicity in applying the technique. Therefore, the correct answer is option 'A' - mesh analysis can be used for planar circuits.