Passage: dear sir or madam

i am responding to your advertisement in the may 1, 2007, issue of the atlanta journal constitution for a full-time salesperson for summer employment. i am very much interested in being considered for this position. it would be really cool to work in a store that sells clothes for teens.

what is the correct punctuation for the salutation of this letter?
a) leave as is
b) dear sir or madam;
c) dear sir or madam:
d) dear sir, or madam

Healthcare costs are becoming an issue for many americans. in just two years, the average family has seen an increase of 3 percent in insurance costs. the increase rises to 25 percent when you include families who buy insurance on an exchange. at this rate, health care will soon be completely unaffordable for most americans. therefore, lowering the cost of health insurance must be a priority for lawmakers. which statement best explains why the argument is logical? a.)the argument incorporates empirical and anecdotal evidence. b.)the argument includes a strong counterclaim and a fair rebuttal. c.)the argument contains relevant reasons supported with facts and data. d.)the argument includes a personal experience as an emotional appeal.