1. )which of the following has caused U.S states to sometime have very different laws on the same topic?

Considering that, because of how the the U.S. Government works, laws can widely vary from State to State. People have different opinions and groups might organize themselves in very different ways. Considering this, the correct answer is:

d.) citizens of each states often have differing opinions as to what should become law

2.) the federal government withholding funding in order to force states to comply with federal regulations falls under which category of federalism?

If the government is withholding, it is also the one making the distribution of income, which consists in a fiscal situation. That leads us to answer

b.) fiscal federalism

3.) the tenth amendment to the U.S constitution states “The powers no delegated to the united states by the constitution nor prohibited by it to the states are reserved to the states respectively or to the people” what effect does this have on local governments?

The texts means that everything that is not in the constitution is left for the States and the people of the country to take care of, including urban organization, public building maintenance and so on

a.) it causes local governments to take on many day to day responsibilities