An increase in hours of television viewing leads to increases in the sales of snack foods. this is an example of a
a. research question
b. descriptive hypothesis
c. correlational hypothesis
d. causal hypothesis

This is not a question (it's not in the form of a question, but in form of a statement) so it's also not a research question.

It's therefore a hypothesis. It suggests that one thing leads to (causes) another - so the correct answer is d. causal hypothesis.

Here's an example using the safe fopen:

FILE* customer = NULL;
fopen_s(&customer, "test.txt", "w");
char* msg = "mary smith";
fwrite(msg, sizeof(char), strlen(msg), customer);
fclose(customer);