Step 1: Match each item.
- Idli: Fermented rice–lentil batter, hence process = Fermentation (2).
- Parboiled rice: Produced by partial boiling of paddy, which involves starch gelatinization, so process = Gelatinization (3).
- Soda beverage: Carbonated soft drink, so process = Carbonation (4).
- Cookies: Made by baking dough, so process = Baking (1).
Step 2: Sequence.
\[
P-2, Q-3, R-4, S-1
\]
Final Answer:
\[
\boxed{\text{(A) P-2; Q-3; R-4; S-1}}
\]