Http://i68.tinypic.com/1zfh081.jpg - Question 10 why is the answer (D)..?

10.
Two types of particles can conduct electricity : namely, delocalized electrons and mobile ions.

X is a metal, which can conduct electricity by delocalized electrons (sometimes known as free electrons). Note that electrons can conduct electricity only when they are delocalized (that means the electrons are moving between atoms). In this MC question, "electrons" is understood as "delocalized electrons".

XO is a compound formed from a metal X and a non-metal O. The ionic compound dissociates in water to give X²⁺ cations and O²⁻ anions (actually they react with water to give OH⁻ ions). In aqueous solution, the cations and anions are mobile and can thus conduct electricity.

XSO₄ is an ionic compound, which dissociates in water to give X²⁺ cations and SO₄²⁻ anions. In aqueous solution, the ions are mobile and can thus conduct electricity.

...... The answer is : D. electrons, cations and anions, cations and anions