To find the assumption on which the author of the advertisement relies, an answer choice with truthful information must be selected in order for the passage argument to be accurate. To do this, the thrust of the passage needs to be determined.

Option A - Incorrect
This cannot be validated from the passage as we do not know anything about the weight of the traditional binoculars.

Option B - Incorrect
This answer choice goes too far in its assumption with its use of the extreme word "only".

Option C - Correct
If a reader uses Avian Oculars for his or her next bird watching trip, he/she will see through the habitats of the world's rare species.

Option D - Incorrect
The price for Avian Oculars and Traditional binoculars were not stated in the passage. So, we cannot know if they are similar or not

Option E - Incorrect
This is not true! That, Avian Oculars were designed to suit the features demanded by enthusiasts for profit maximization doesn't mean that Birding enthusiasts are the ones who determine the product specifications.