A buildup of charges in an object is called

Static Electricity.

Explanation:

Static electricity is defined as 'an electric charge that has built up on an insulated body, often due to friction.' It is an outcome of the disparity among the positive, as well as, negative charges residing in a body or object and causes the charge to build up on the surface of the body. The accumulation of electric charges on the objects like wool, hair, silk, plastic, etc. causes them to possess static electricity. These charges stay on the surface until it is discharged or released through a source. Thus, 'static electricity' is the correct answer.

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.  

the answer your looking for is c).