Concept:Public opinion is formed through open platforms where citizens express or receive political views.Explanation:Elections allow people to express their preferences and shape public opinion.Mass media spreads information and influences how the public thinks.Political parties educate and mobilise citizens, helping to form opinions.The cabinet is not such a channel because it is a decision-making body of senior government officials.The cabinet does not exist to form public opinion; instead, it responds to and acts on public opinion.Answer:A. Cabinet