S (Strengthen): Conclusion Shifting entrance will generate enough money to pay for renovations
Missing info : Will consultant’s recommendation have any undesirable impact.
If yes, conclusion will NOT be strengthened.
If no, the conclusion will be strengthened.

(A) More train commuters are employed in businesses located on Main Street than in businesses located on the adjoining side street.
Irrelevant : Where commuters are employed does not matter here.

(B) A reliable survey of Flowertown's commuters showed that virtually none of them would use the train any less frequently if the station's entrance were moved.
Correct. This option eliminate a possible negative effect of consultant’s recommendation

(C) The high-rent block of Flowertown's Main Street includes several buildings whose owners currently seek to replace long-standing tenants lost in recent months.
At the most, this option says that the recommendation may not have a desired effect as other high rent spaces in the locality are on lease and hence the train station’s space may or may not find a taker.

(D) If the station's entrance were moved, the train company would need to begin costly renovations to its Main Street entrance space.
Again, it says that to implement the recommendation, the train station will need extra money and thus possibly weaken the argument.

(E) Ridership on Flowertown trains declined only slightly from 1970 to 1985 while other train companies lost large numbers of commuters.
Irrelevant, as the option does not specify the reason for less decline in the ridership

Take away:
Let’s say X (rents from leasing) & Y (train commuters) form Z (revenues), and p (recommendation of the consultant) affects X.
Then always look for effects of P on Y.