Select the most appropriate option that can substitute the underlined words in the given sentence.

Though very informative, Shweta’s article was mercilessly rejected of the editor.

The correct answer is "was mercilessly rejected by".

Step-by-step explanation:

1. Analyze the sentence structure:
The given sentence is: "Though very informative, Shweta’s article was mercilessly rejected of the editor."
Here, the action ("rejected") is performed by the agent ("the editor"). This indicates that the clause is in the passive voice.

2. Identify the prepositional error:
In passive voice sentences, the agent performing the action is introduced by the preposition "by" (e.g., "rejected by the editor"), not "of", "on", or "each".

3. Evaluate the options:
- "was mercilessly rejected of": Incorrect usage of the preposition "of".
- "was mercilessly rejected on": Incorrect usage of the preposition "on".
- "was mercilessly rejected each": Grammatically incorrect and makes no sense in this context.
- "was mercilessly rejected by": Correct passive construction using the appropriate preposition "by".

Therefore, substituting the underlined phrase with "was mercilessly rejected by" makes the sentence grammatically correct: "Though very informative, Shweta’s article was mercilessly rejected by the editor."