15.
The problem with B is that it's too general and does not actually mention Write comapny at all. If sales grow, that does not mean Write will have a larger piece of the cake.
With E, if Write's leads are not cheaper, and will remain so with the new leads, the way for its sales to grow is through the effect of the 'design' it will initiate, which will attract new cutomers.
14. I picked E.