Option 1: Tetanus - BCG
BCG (Bacillus Calmette-Gu鲩n) is a vaccine used to protect against tuberculosis, not tetanus. Therefore, this pairing is incorrect.
Option 2: Tuberculosis - ATS
ATS (Antitetanus serum) is used to treat tetanus, not tuberculosis. Therefore, this pairing is incorrect.
Option 3: Malaria - Chloroquin
Chloroquin is a medication used to treat and prevent malaria. This pairing is correct.
Option 4: Scurvy - Thiamine
Thiamine is a vitamin (B1), and it is not used to treat scurvy. Scurvy is caused by a deficiency of vitamin C. Therefore, this pairing is incorrect.
In conclusion, the correct answer is option 3: Malaria - Chloroquin.