"If Farmer asserts a claim based on negligence against Utility for crop damages, will Farmer prevail?
No, because Utility was not negligent. 
No as to 1976 crop damage, because Farmer did not mitigate damages by selling his farm in 1975. 
Yes as to 20 percent of his crop damage, because use of available equipment would have reduced the fumes by 20 percent. 
Yes, because operation of the plant constitutes a nuisance