Cobalt ions form complex ions with water and chloride as shown in the reaction. The left side of the reaction is pink, and the right side of the reaction is blue.

Co(H2O)62+ + 4Cl– + heat ⇄ CoCl42–+ 6H2O

Which statement about the system at equilibrium is correct?
Responses-

a- Heating a blue solution will turn it purple.

b- Adding water to a purple solution will turn it blue.

c- Adding hydrogen chloride (HCl) to a blue solution will turn it purple.

d- Cooling a purple solution will turn it pink.

d- Cooling a purple solution will turn it pink.

d- Cooling a purple solution will turn it pink.