Which statement best defines an electric field? force per unit charge on a negative source charge force per unit charge on a negative test chargeforce per unit charge on a positive source chargeforce per unit charge on a positive test charge

a region around a charged particle or object within which a force would be exerted on other charged particles or objects.

thats what a electric field is so the answer must be d

Force per unit charge on a positive test charge

Explanation:

There exist a force between two charged particles as per Coulomb's law. It states that the force is directly proportional to the product of charges and inversely proportional to the square of distance between them. It is given by :

Where, q is positive test charge

Q is source charge

The area surrounded by electric charge is called electric field. It is defined as the electric force acting per unit charge.

or

Hence, the statement that defines an electric field is " Force per unit charge on a positive test charge ".