No, definately not. If so there is no point in having people elected, just let the companies pay for their views.
C. According to how they perceive their constituants would vote were they allowed.
Not directly, no. If this was the case then each issue should be voted on by the people themselves directly. Again, no need for the government except as a tabulation system.
B. According to their party affiliation's beliefs.
How did that differ from D?
A. According to their conscience/beliefs.
Bingo. People are elected to represent their people. While we know that we won't always agree all the time, the goal is to pick someone who will reason about something in a way similar to you. If you vote for someone sharing similar consience/beleifs (or at least one with amicable beleifs) then you'll do just fine.