Tip: If you are aware of your action nouns vs. concrete nouns, you will notice that "production" and "harvest" are both action nouns so in B they are parallel.
A few Examples:
Action nouns
change
growth
break
work
arrival
eat
eruption
explosion
demolition
suspension
etc...
-Gerunds (ending in -ing) can also be action nouns)-
eating
arriving
driving
walking
etc...
Concrete nouns
student
fire fighter
dog
pencil
rock
trees
rocking chair
smog
etc...
Don't mix these two types of nouns while you're scanning for parallelism/comparisons. Master these and see how much of a breeze parallelism begins to be.
A few Examples:
Action nouns
change
growth
break
work
arrival
eat
eruption
explosion
demolition
suspension
etc...
-Gerunds (ending in -ing) can also be action nouns)-
eating
arriving
driving
walking
etc...
Concrete nouns
student
fire fighter
dog
pencil
rock
trees
rocking chair
smog
etc...
Don't mix these two types of nouns while you're scanning for parallelism/comparisons. Master these and see how much of a breeze parallelism begins to be.