If p, q and r are simple propositions such that $(\mathrm{p}\wedge \mathrm{q})\wedge (\mathrm{q}\wedge \mathrm{r})$ is true, then

• A

  p, q and r are all false 

• B

  p, q and r are all true

• C

  p, q are true and r is false

• D

  p is true and q, r are false