How did white southerners argue in support of slavery? PLEASE HELP

In a group discussion, which of these is the best example of synthesis claims into a single conclusion?

It can be inferred that the dramatic increase in defense spending by germany was the result of. (a) attempts by great britain to take german colonies. ( b) fear of a two-front war against france and russia (c) the need to put down a communist rebellion (d) a competition with the allies to produce atomic weapons

Who was the first explorer to sail all the way down the mississippi river