in which sentence is the essential clause underlined

A. Eve's sister, {who loves opera,} took her to a performance
B. Eve, {holding her program,} waited for the curtain to go up
C. The soprano, {visiting from canada} had long black hair***
d. The person {who sells souvenirs} is in the lobby

i think its D

D. The person {who sells souvenirs} is in the lobby

The sentence with the essential clause underlined is:

D. The person {who sells souvenirs} is in the lobby.

To identify the sentence with the essential clause, you need to look for the underlined clause or phrase that is necessary to the meaning of the sentence. An essential clause, also known as a restrictive clause, provides information that is essential to understanding the noun it is modifying.

Let's analyze each sentence:

A. Eve's sister, {who loves opera,} took her to a performance.
In this sentence, the underlined clause "{who loves opera}" is non-essential because it provides additional information about Eve's sister but does not change the essential meaning of the sentence.

B. Eve, {holding her program,} waited for the curtain to go up.
The underlined phrase "{holding her program}" is also non-essential because it provides additional information about what Eve is doing but is not necessary to understand the main point of the sentence.

C. The soprano, {visiting from Canada}, had long black hair.
In this sentence, the underlined phrase "{visiting from Canada}" is non-essential because it provides additional information about the soprano, but it is not crucial to understanding the main point of the sentence.

D. The person {who sells souvenirs} is in the lobby.
The underlined clause "{who sells souvenirs}" is essential because it identifies which person is being referred to. Without this clause, the sentence would be incomplete.

Therefore, the sentence with the underlined essential clause is option D:

D. The person {who sells souvenirs} is in the lobby.

That is not a clause; it's a participial phrase. It doesn't have a subject and a verb.