Question

Read the excerpt from The Riddle of the Rosetta Stone.

Answer 1

The correct answer is: more valuable and fame.

First of all, there are only two options refering to the Rosetta Stone: "more valuable and famed" and "rather small and piece of rock". The other options refer to things only related to it, they don't describe it directly.

Whitin those two options describing the Rosetta Stone, "rather small and piece of rock" don't give any positive value, they are describing the stone in a way it seems something very common, just another stone that has nothing in particular. Instead, with "more valuable and fame" you can picture something important, worth a lot of money and known by everyone.  

Answer 2

The words in the excerpt stated above which best show that Giblin views the Rosetta Stone as very important are the following: more valuable and famed.

The adjective "more valuable" indicates value and worthy while "famed" indicates popularity or highly acclaimed.