Advertisement: When your car’s engine is running at its normal operating temperature, any major brand of motor oil will protect it about as well as Tuff does. When the engine is cold, it is a different story: Tuff motor oil flows better at lower temperatures than its major competitors do. So, if you want your car’s engine to have maximum protection, you should use Tuff. 

Which of the following, if true, most strengthens the argument in the advertisement? 

(A) Tuff motor oil provides above-average protection for engines that happen to overheat. 

(B) Tuff motor oil is periodically supplied free of charge to automobile manufacturers to use in factory-new cars. 

(C) Tuff motor oil’s share of the engine oil market peaked three years ago. 

(D) Tuff motor oil, like any motor oil, is thicker and flows less freely at cold temperatures than at hot temperatures. 

(E) Tuff motor oil is manufactured at only one refinery and shipped from there to all markets. 



We need to find an option that strengthens the advertisement. 

We already know from the premises that Tuff oil flows better at lower temperatures than its major competitors. We also know that at normal temperature, any major brand of oil will protect the car's engines about as well as Tuff does. We need to find an option that strengthens the conclusion- "So, if you want your car’s engine to have maximum protection, you should use Tuff." 

(D) Tuff motor oil, like any motor oil, is thicker and flows less freely at cold temperatures than at hot temperatures. We already know that at cold temperatures, Tuff motor oil performs better than its competitors. There's nothing that adds to the conclusion. 

Option A on the other hand tells us that Tuff motor oil provides above-average protection for engines that happen to overheat. At normal temperatures, any major brand of oil will protect the car's engines about as well as Tuff does. At cold temperatures, it performs better than its competitors. Option A says that even when the engine overheats, its performance is above average. This strengthens our conclusion that you should use Tuff if you want maximum protection for your car's engine.


B- Free of charge or not is not relevant to the argument. Eliminate

C- Irrelevant to the argument- Eliminate

D- It is already stated in the premise that "Tuff motor oil flows better at lower temperatures than its major competitors do". It doesn't add to the conclusion. Eliminate

E-  Irrelevant to the argument- Eliminate