In a certain city, 60 percent of the registered voters are Democrats and the rest are Republicans. In a mayoral race, if 70 percent of the registered voters who are Democrats and 20 percent of the registered voters who are Republicans are expected to vote for Candidate A, what percent of the registered voters are expected to vote for Candidate A ?  Choose the correct choice from the following:
A) 50 %
B) 53 %
C) 54 %
D) 55 %
E) 57 %

Rationale: "say there are total of 100 registered voters in that city . thus 60 are democrats and 40 are republicans . 60 * 0.70 = 42 democrats are expected to vote for candidate a ; 40 * 0.20 = 8 republicans are expected to vote for candidate a . thus total of 42 + 8 = 50 registered voters are expected to vote for candidate a , which is 50 % of the total number of registered voters . answer : a"
Answer: A