Question

what is the answer/why. if the answer is invalid, what is the additional info needed to make it valid?

Answer 1

given :

AB = CD

AB // CD

AB ⊥ CD

So, it is not logic to AB // CD and AB ⊥ CD

So, the answer is the conclusion is invalid

To make the conclusion ABCD is a rectangle, the additional information will be:

AB ⊥ BD , AC // BD