Which sentence is punctuated correctly?

a.
my father has studied these languages: russian; german; and arabic.

b.
on their vacation trip to europe, the richardsons visited vienna, austria; munich, germany; and warsaw, poland.

c.
the dates of the big conventions are may 18-20; july 13-15; and august 17-19.

d.
james city county; virginia, st. mary's county; maryland, and york county; maine are some of the oldest counties in the united states.

Based on this excerpt from "stopping by woods on a snowy evening" by robert frost, which statement best summarizes a theme in the poem? the woods are lovely dark and deep but i have promises to keep and miles to go before i sleep and miles to go before i sleep

How can you tell that the text is from a biography

Making ethical decisions in the health care setting can be confusing. ethical dilemmas are found in almost every aspect of the health care delivery system. the word ethics comes from the greek ethos, meaning custom, usage, or character. ethical study is related to philosophy, the pursuit of wisdom. ethical theories attempt to systemize, defend, and recommend concepts of right and wrong behavior. we all have opinions and beliefs about ethics, even if we’re not fully conscious of them. based on the paragraph, what does ethical mean? being in accordance with accepted principles of right and wrong that govern the conduct of a profession of, relating to, or based on philosophy restricted to sale only based on a doctor's prescription knowledge of what's proper or reasonable; using good sense or judgment in a professional setting