Each option in this question represents a different possible answer to which southern state in India shares a border with the maximum number of other states. In option 1 and 2, Andhra Pradesh and Karnataka are suggested respectively as the states that share a border with the most states, suggesting that the other states do not. Option 3 combines both Andhra Pradesh and Karnataka in the answer, indicating that they both share the same maximum number of borders with other states. Option 4 sees Tamil Nadu and Kerala as the states with the greatest number of shared borders, arguing against the others. The correct answer, option 3, indicates that both Andhra Pradesh and Karnataka share borders with the maximum number of states, over the other options suggested.