Ive been stuck on this and everyone keeps giving me different answers please help

Which of the following could be the graph of the equation y = -2x + 5

Arefrigeration system at your company uses temperature sensors fixed to read celsius (°c) values, but the system operators in your control room understand only the fahrenheit scale. you have been asked to make a fahrenheit (°f) label for the high temperature alarm, which is set to ring whenever the system temperature rises above –10°c. what fahrenheit value should you write on the label

What is perpendicular to y=-1/2x+11