Which pair of main points best meets the guideline that main points be related? a. 1. Recycling at home is important for each household. 2. Environmental sustainability is a relatively new industry. b. 1. Sustainable business practices can reduce costs. 2. Solar energy is on the rise. c. 1. Solar energy is on the rise. 2. Many businesses are not environmentally responsible. d. 1. Sustainable business practices can reduce costs. 2. Environmental responsibility attracts investors