Critical Reasoning

When Cortez arrived in Mexico in A.D. 1519, he observed the inhabitants playing a ceremonial game with a rubber ball. The pre-Columbian inhabitants of Mexico began to use rubber around A.D. 1000. Thus,we can be sure that the game must have originated sometime between approximately A.D. 1000 and
Cortez' arrival.

The conclusion reached above depends on which one of the following assumptions?

(A) The pre-Columbian inhabitants of Mexico played games on all ceremonial occasions.
(B) The making of rubber balls was one of the earliest uses of rubber by the inhabitants of Mexico.
(C) The ceremonial game referred to was popular throughout Mexico.
(D) The game had been played since its inception with a rubber ball.
(E) The dating of the first use of rubber in Mexico was due to Cortez.

OA - D

Premise 1 - Cortez observed the ceremonial game in 1519 AD.
Premise 2 - inhabitants began to use rubber around 1000 AD.

Conclusion - the game originated between 1000-1519 AD.

the assumption must link the premise to the conclusion.

Option A - Incorrect.
Whether they played ceremonial games on all or few occasions has nothing to do with when the game originated.

Option B - Incorrect.
Even if it wasn't the earliest uses of rubber by inhabitants of Mexico, it does not affect the conclusion.

Option C - Incorrect.
Popularity has nothing to do with when the game originated.

Option D - Correct Answer.
If the game was played with something else, then it is quite possible that the game was played before the use of rubber, i.e. before 1000 AD.

Option E - Incorrect.
the person who dated the first use of rubber is irrelevant. (As long as the dates given are accurate).