I believe the answer is A+b. Plz mark as brainliest if correct.
Answer
The skill set of a person may be valuable or non-valuable based on what the demand for a certain product is. The more value for a skill the higher of a wage because the employer would want to keep the person with the skill. Like if having a cell phone is in high demand, people who have a skill in engineering will be paid more because they need someone who can program the phone to be the best.
My option is that the closer they are to their sources of energy the more they produce and more materials to complete their product.