discrete mathematics – Rule of inference. Is the argument valid?


The premises are:

  1. $neg p vee r$
  2. $q rightarrow (k wedge t)$
  3. $p rightarrow q$
  4. $neg(k wedge t)$

The conclusion is: $r$
Show that the following argument is valid by using rules of inference.

I unable to solve this question but my lecturer said there is nothing wrong with this question. So, is the following arguments valid? Please give your answer with prove and explanation.

Any help will be appreciated.
Thanks