Option 1: (A), (B) and (C) only -> Incorrect because Digboi is not an SPR location; it's a historic oil town with a refinery.
Option 2: (A), (B) and (D) only -> Incorrect because Digboi is not an SPR location.
Option 3: (A), (C) and (D) only -> Includes all three correct SPR locations: Padur (2.5 MMT), Mangaluru (1.5 MMT), and Visakhapatnam (1.33 MMT), totaling 5.33 MMT.
Option 4: (B), (C) and (D) only -> Incorrect because Digboi is not an SPR location and Padur is missing.
Hence, Option 3: (A), (C) and (D) only -> India's three operational SPR facilities are located at Padur (Karnataka), Mangaluru (Karnataka), and Visakhapatnam (Andhra Pradesh), established by ISPRL to ensure energy security during supply disruptions -> correct