In Question $4$:

$1.$ It might be valid because after the pre condition is satisfied, s is incremented by $1$ therefore, we can say that It might satisfy the post condition.

$2.$ It might be invalid, because after the execution of s the post condition $,$ight ot satisfy the given triple.

$3.$ It might be Invalid, because as s and k are incremented after execution the post condition might not be satisfied.

$4.$ It might be Valid, because the post condition refers to s$0,$ the execution of s doesn't affect it$.$

please help me with these questions.