Conditional dependence/ independence

Question

In which of the situations are A and B independent if A is performed first?

1. A = Pick a card from a pile, put it back B = Pick a card from the same pile
2. A = Pick two cards from the pile, put one back and keep one B = Pick one card from the pile
3. A = Pick one card from the pile and keep it B = Pick one card from another pile and keep it

Answer 1

In the first scenario, $A$ and $B$ are independent. Whether or not I pick up a card from the pile and put it back has no effect on the available cards to pick from for $B$.

In the second scenario, $A$ and $B$ are dependent. Depending on which card I keep in $A$, the choices for $B$ change. So the outcome of $B$ depends on what card I picked in $A$.

In the final scenario, $A$ and $B$ are independent again. No matter which card i pick from the first pile for $A$, it does not affect the cards in the second pile for $B$ so the possible outcomes for $B$ are unchanged and therefore do not depend on $A$.