You have developed a prototype for a digital ring that uses infrared $($IR$)$ technology, allowing users to control a cursor by making a fist gesture and aiming at targets on a desktop

or within a virtual reality environment. Selection is achieved when the IR ray remains over a target for $500$ milliseconds. Before progressing towards product development,

which two of the following challenges should be prioritized for resolution?

User fatigue

Color accuracy

Learnability

Scalability

Privacy and security

Midas touch problem

Environmental impact