C, Compound. This is because there is just a independent clause and dependent clause. As in complex compound complex there would be more dependent clauses.
We cant help if u dont have the other parts of the question
A stable income
A stable job
Legally owning property
Possibly a family
Good health
I would assume, the best way to measure if it's achievable would be making a graph of various ages and seeing when most people achieve these indicators and how many do it.
Claims and support are related because claims are statements that are made by authors in relation to some subject matter that are backed up by "support" or evidence. Therefore, based upon these options, "An author will use support to back up a claim." This claim and support are what authors use to create arguments in writing to make a point and to express a perspective on a particular issue.
A comma and a conjunction always work well but it really depends on the sentences you are combining.
