Concept:Sentence arrangement is based on logical flow and grammatical connections.
Explanation:S1 describes how an Indian state lost its independence by signing a Subsidiary Alliance.
Q follows naturally: “It lost the right of self‑defence” — this directly explains the loss mentioned in S1.
P and S are parallel phrases listing what else was lost: “of maintaining diplomatic relations” and “and of settling its disputes”.
R completes the list: “with its neighbours”.
Thus Q‑P‑S‑R forms the correct sentence: “It lost the right of self‑defence, of maintaining diplomatic relations and of settling its disputes with its neighbours.”
S6 then confirms the ruler lost all sovereignty in external matters.
Answer:C. Q P S R