The vapor pressure of a solution prepared by mixing two liquids, R, p*=80mmHg, and S, p*=120mmHg is found to be 86 mmHg when X_r=0.4. Which of the following is correct about these solutions?

A) exhibit favorable interactions
B) are partially miscible ******
C) boil more readily then ideal solutions
D)display ideal behavior

I know it's not D but I'm thinkin it's B.