The best answer to the given question is B.
When a variable "varies inversely as y," it means that as y increases, the variable decreases, and vice versa. This relationship is expressed mathematically as:
variable = k/y
where k is a constant.
When a variable "varies directly as y," it means that as y increases, the variable also increases, and vice versa. This relationship is expressed mathematically as:
variable = k*y
where k is a constant.
Option (a) does not provide any information about the relationship between variables. Option (c) and (d) provide incomplete information as they do not specify the variable that varies with y. Option (b) correctly explains the two types of relationships between variables and their mathematical expressions.
Option B is the best answer.