If no loss or gain of electrons occur by mixing of two atoms, we say that they may be attached to each other due to
A proton attraction
B neutron attraction
C sharing of electrons
D opposite charges
<

The correct option is option C

Explanation:

Loss or gain of electron(s) occurs in a type of attraction known as electrovalent or ionic attraction. In this type, there is transfer (or loss) of electron(s) from a metal atom to become positively charged while a nonmetal accepts (or gains) this electron to become negatively charged.

When this does not happen, two metal atoms can become attached by sharing the same electrons through a form of attraction known as covalent bonding. Here, the two atoms share electrons (known as shared pair) together to achieve there octet configuration on the outermost shell.