Abattery produces , which is current that flows in only one direction.

The correct answer to the question is direct current i.e a battery produces direct current which is the current that flows in only one direction.

EXPLANATION:

Before coming into any conclusion, first we have to understand the types of current. There are generally two types of current which are known as direct current and alternating current.

Direct current:

A direct current is the current which moves in one direction only. It may be a steady current or a pulsating direct current.

A steady current is a time independent current i.e its magnitude is constant with time. It is also known as a stationary current. For instance, the current flowing through a battery.

A pulsating dc current is a type of dc current in which the magnitude of the current changes with time, but moves in one direction. For instance, the current produced in a junction diode rectifier.

Alternating current: Alternating current is the type of fluctuating current whose magnitude changes continuously and direction changes periodically.

In the given question, the current produced in a  battery is flowing in one direction only.

Hence, the correct answer to the question will be direct current.

a.   mass number from atomic number