(A) The Eiffel Tower was designed by
(B) held in Paris that year
(C) Gustave Eiffel as the entrance arch
(D) for the 1889 World's Fair

In the following question, a grammatically correct and meaningful sentence is given which is divided into four parts namely (A), (B), (C) and (D). Arrange these four parts to make a contextually and grammatically meaningful sentence.

The correct option is ACDB.

To form a grammatically correct and meaningful sentence, let us analyze the logical flow of the given fragments:
1. Part (A) ("The Eiffel Tower was designed by") introduces the subject ("The Eiffel Tower") and the passive verb ("was designed by"), which requires an agent following the preposition "by".
2. Part (C) ("Gustave Eiffel as the entrance arch") provides the agent ("Gustave Eiffel") and describes the intended function ("as the entrance arch").
3. Part (D) ("for the 1889 World's Fair") completes the phrase by indicating the event for which the arch was constructed.
4. Part (B) ("held in Paris that year") functions as a modifying phrase providing context about the 1889 World's Fair.

Arranging the parts in the sequence A → C → D → B forms a logical and grammatically complete sentence:
"The Eiffel Tower was designed by Gustave Eiffel as the entrance arch for the 1889 World's Fair held in Paris that year."