If 60 seconds are in a minute, 60 minutes in an hour, and 24 hours in a day, then 86,400 seconds are in a day. what type of reasoning is this?

is it a. inductive or b. deductive
?

Let's define both terms first. Inductive reasoning is a conclusion that you get out of a series of observation. However, this may be true or not. But for deductive reasoning, you reach a conclusion that you get out of a series of observations that are also supported by facts. These are all true. 

Since all the statements are based on facts, this is a deductive reasoning.

The answer is B. deductive.