Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 31 to 35.

The universal symbol of the Internet era communications, the @ sign used in e-mail addresses to signify the word 'at', is actually a 500-year-old invention of Italian merchants, a Rome academic has revealed. Giorgio Stabile, a science professor at La Sapienza University, ______(31) to have stumbled on the earliest known example of the symbol's use, as a(n) ______(32) of a measure of weight or volume. He says the sign represents an amphora, a measure of capacity based on the terracotta jars used to transport grain and liquid in the ancient Mediterranean world.

The professor unearthed the ancient symbol in the course of research for a visual history of the 20th century, to be published by the Treccani Encyclopedia. The first ______(33) instance of its use, he says, occurred in a letter written by a Florentine merchant on May 4, 1536. He says the sign made its way along trade routes to northern Europe, where it came to represent "at the price of" - its contemporary accountancy ______(34).

Professor Stabile believes that Italian banks may possess even earlier documents ______(35) the symbol lying forgotten in their archives. The oldest example could be of great value. It could be used for publicity purposes and to enhance the prestige of the institution that owned it, he says. The race is on between the mercantile world and the banking world to see who has the oldest documentation of @.

Đáp án đúng là: D
Giải thích
- proof (n): chứng cớ, bằng chứng (dùng để xác nhận một sự việc đúng hay sai, có sức thuyết phục cao)
- sign (n): dấu hiệu
- evidence (n): chứng cớ, bằng chứng (dùng để chứng minh một điều gì, thu được từ nhân chứng, tfai liệu
hoặc bất cứ nguồn nào khác)
- indication (n): sự biểu thị, dấu hiệu  như một dấu hiệu của một thước đo trọng lượng hoặc khối lượng.
Dựa vào ngữ nghĩa  chọn D