(A) Only I, II and III are correct.
A political party has three components: the leaders, the active members, and the followers. Pressure groups are separate from political parties.
Source: Chapter 4, Meaning (Components of a Political Party)
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The textbook explicitly states: "A political party has three components: the leaders, the active members and the followers." Pressure groups are mentioned elsewhere as extensions of parties among different sections of society, but they are not components of a political party. Students must not confuse the two.