Fill in the blank with suitable prepositions:

How have you come __________ such a precious diamond?

(A) By
(B) Upon
(C) Across
(D) to
(E) over

Choose the correct answer from the options given below:

(A) and (C) only

The correct answer is Option (3) - (A) and (C) only

1. By: This is used to indicate how something is obtained or achieved. "How have you come by such a precious diamond?" means how did you acquire it.

2. Across: This is used to indicate encountering something unexpectedly. "How have you come across such a precious diamond?" means how did you find or discover it.

 Other Options:

• (B) Upon: While "come upon" can mean to encounter unexpectedly, it is less commonly used in this context.
• (D) To: This does not fit the sentence grammatically or contextually.
• (E) Over: This is not appropriate for this context.

Correct Sentence:

"How have you come by such a precious diamond?" or
"How have you come across such a precious diamond?"