In Order to Increase Typing Speed, Minisoft Inc

In order to increase typing speed, Minisoft Inc. has redesigned its keyboard and provided a chime that is related to typing speed. The company wants to know if its innovations affect typing speed. What are the independent and dependent variables in this proposed study?

A) The dependent variable is the chime; the independent variables are the chime and typing speed.
B) The dependent variable is speed of typing; the independent variables are the keyboard design and the chime.
C) The dependent variable is keyboard design; the independent variables are the speed of typing and the chime.
D) The dependent variable is the number of errors made; the independent variables are the chime and the speed of typing.