8. 8.71 Two methods of weed control in an irrigation ditch are under consideration. Method A involves lining at a first cost of $4,000, a life of 20 years, and M&O costs of $3 per mile per year. Method B involves spraying a chemical that costs $40 per gallon. One gallon will treat 8 miles, but the treatment must be applied 4 times per year. In determining the number of miles per year that results in breakeven, the variable cost for method B is closest to: 1. $5/mile 2. $15/mile 3. $20/mile 4. $30/mile