B. Discuss the implications of the following: Kant may say: "We have a 'duty' not to throw trash out of the car window on the freeway."

This is somewhat vague and you may get a better answer if you
will clarify as to what sort of implications you are thinking
of...

To me, the major implication of this statement is that it
claims that Kant is concerned with the impact of our actions on society, not simply with whether
they are personally moral.  When we use the term "duty" we tend to refer to things that we must
do (or not do) because of our place in a society.  Duties tend to be our committments to other
people -- we have a duty to our spouses and our children.

By saying
that not throwing trash is a duty rather than a moral imperative, the statement is implying that
Kant would think of this action in terms of its impact on other rather than in terms of our own
personal morality.