Answer:
B and C and A (most likely if it's broad and specific reasons that you go into more detail in the body paragraphs.)
Step-by-step explanation:
A thesis needs to support three main things: audience, purpose, and content. A thesis is a claim, thus your topic and your perspective on the claim. A traditional format is:
While [Counterargument], {topic} is/was/(what happened?) by/because of {supporting reason(s)}.
You go into further detail for each supporting reason in your body paragraphs.
An example of a thesis:
While a number of economic factors caused the stock market crash of 1929, the losses were made worse by uninformed first-time investors who made poor financial decisions.
The while part is the counterargument. The topic is losses. The reason supporting the claim is that uninformed first-time investors made poor financial decisions.