In levelling, the following staff readings were observed involving an inverted staff, a = 2.915 and b = -2.028. what is the rise or fall from a to b (only enter numeric answer, no alpha)?

a straight line sloped

the answer would most likely be c, because if it's a comical piece of information, it may likely not be true, if it's a site that allows anybody to edit the content, it could mean a five year old is typing the info, and if it's a tv show produced by a celeb, it may have a biased opinion.