Answer: Option (a) is the correct answer.
Step-by-step explanation:
A compound formed by sharing of electrons is known as a covalent compound. Whereas a compound formed by donating electrons is known as ionic bond.
Also, it is known that an ionic or polar compound is soluble in polar solvent like water. And a non-polar compound is soluble in a non-polar solvent.
For example, sodium has 11 electrons and chlorine has 17 electrons. So sodium will donate one extra electron to chlorine in order to complete their octet. Hence, it will result in the formation of an ionic compound.
Thus, we can conclude that the statement it is made up of ions that are held together by ionic bonds, is true.