The conduction current in ideal case through a circuit is zero when charge on capacitor is:

Hint: Conduction transfers heat by direct molecular collision. An area of greater kinetic energy will transfer thermal energy to an area with lower kinetic energy. Higher-speed particles will collide with slower speed particles. The slower-speed particles will increase in kinetic energy as a result. Conduction is the process by which heat energy is transmitted through collisions between neighbouring atoms or molecules. These vibrating molecules collide with their neighbouring molecules, making them also vibrate faster. As these molecules collide, thermal energy is transferred via conduction to the rest of the pan. Based on this concept we have to solve this question.

Complete step-by-step answer:
In its basic form, a capacitor consists of two or more parallel conductive (metal) plates which are not connected or touching each other, but are electrically separated either by air or by some form of a good insulating material such as waxed paper, mica, ceramic, plastic or some form of a liquid gel.
A capacitor (originally known as a condenser) is a passive two-terminal electrical component used to store energy electrostatically in an electric field. The forms of practical capacitors vary widely, but all contain at least two electrical conductors (plates) separated by a dielectric (i.e., insulator).
Capacitors are charged through a resistor. Initially, when the charge is zero, the potential across the capacitor is zero. Hence maximum current flows through the circuit.
As the potential builds up, the current reduces. When the capacitor builds charges fully, the potential difference across the resistor becomes zero and hence the current will be zero.

Note: We know that conduction current is the electric current which exists in a conductor when the electrons flow in the conductor at a uniform rate. So, it is the current in a conductor when the electric field remains constant with respect to time. Displacement current is due to the time-varying electric field. It does not exist under steady conduction. The cause of conduction current is the flow of electrons in the conductor under the effect of applied potential difference.
It is known that conventional Current assumes that current flows out of the positive terminal, through the circuit and into the negative terminal of the source. Electron Flow is what actually happens and electrons flow out of the negative terminal, through the circuit and into the positive terminal of the source.