A->B

universeme

When I see A->B structure in the stimulus,

The right answers should be
1) A->B
2) /B->/A (contrapositive)

The wrong answers should be
1) A->/B (logical negation?)
2) /B->A (logical negation?)
3) /A->/B (mistaken negation)
4) B->A (mistaken reversal)

And these are irrelevant (could be true) ?
1) /A->B
2) B->/A

MissionLsat

The right answers that you have written is absolutely correct. However , the correct answers that you have written are not always must be false they could be true too. But they cannot be must be true (MBT)

MBT for any conditional statement is only it's contrapositive and nothing else.

For the answers you state are wrong-

1. A arrow /B This is must be false.

2. /B arrow A This is must be false too.

3. /A arrow /B This statement could be true. So this is not always a wrong answer

4. B arrow A This could be true also. So this too is not always a wrong answer.

I would advise you to visit the core curriculum for conditional statement again and clear up the concepts.