The argument depends on which one of the following assumptions?

The argument depends on which one of the following assumptions?
(A) Mr. Cooper does not teach the hard-sell method. Nor does he teach the I’ll-be-your-pal method. Instead, he stresses the professional-client relationship.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Exercise (Logic I)