Answer:
b. Conducts electricity when dissolved in water
Explanation:
Iron(II) chloride, is the chemical compound with formula FeCl2.
It is a solid with a high melting point of about 677 degree Celsius or 950 K when in anhydrous form but have lower melting point in hydrated form.
The compound is often off-white. FeCl2 crystallizes from water as the greenish tetrahydrate, which is the form that is most commonly encountered in the laboratory.
There is also a dihydrate. The compound is highly soluble in water, giving pale green solutions.
Explanation:
Copper(II) sulfide reacts with oxygen gas to give solid copper(II) oxide and sulfur trioxide gas.
The reaction is given as:

When 1 mol copper(II) sulfide react with 2 moles of oxygen gas it gives 1 mol of solid copper(II) oxide and 1 mol of sulfur trioxide gas
The gas formed in above reaction that is sulfur trioxide reacts with water to give sulfuric acid or hydrogen sulfate.
The reaction is given as:

1 mol of sulfur trioxide gas reacts with 1 mol of liquid water to produce 1 molo of liquid hydrogen sulfate or sulfuric acid
C, because a homogeneous mixture is evenly mixed.
All those others would be heterogeneous (not evenly mixed).
The sedimentary rock formed when water deposits tiny particles of clay in very thin flat layers is called limestone.