Identify the part of the sentence that contains the grammatical error: "She went to gym despite of her illness."

Introduction / Context:
Error correction questions often focus on common mistakes with prepositions and fixed expressions. In English, certain words form set phrases that must be remembered as a whole, such as "in spite of" and "despite". The sentence "She went to gym despite of her illness" contains such a fixed phrase used incorrectly. Your task is to find which part of the sentence is grammatically wrong.

Given Data / Assumptions:

• The sentence is: "She went to gym despite of her illness."
• The parts offered as options are: "to", "despite", "of", "None of the above" and "gym".
• We assume standard modern English usage.
• Exactly one segment represents the main error that examiners intend to test.

Concept / Approach:
"Despite" is a preposition that is used on its own, followed directly by a noun, pronoun or gerund, as in "despite the rain" or "despite feeling tired". The phrase "despite of" is incorrect. If you wish to use "of", the correct fixed expression is "in spite of", not "despite of". Therefore, in this sentence, the problem is the unnecessary "of" that follows "despite". The rest of the sentence is acceptable in informal English, although some examiners might prefer "to the gym". The core grammar error, however, lies in the phrase "despite of".

Step-by-Step Solution:
Step 1: Focus on the phrase "despite of her illness". Recall that correct usage is "despite her illness" without "of".Step 2: Recognise that the word "despite" itself is fine; it is a correct preposition meaning "in spite of".Step 3: Identify that "of" is the unnecessary and incorrect word here, because it creates the wrong combination "despite of".Step 4: Check the word "to". In everyday speech, "go to gym" is understandable, and adding "the" would improve style but the absence of "the" is less serious than the clear preposition error with "despite".Step 5: Check "gym". This is an appropriate noun and does not cause a grammatical mistake here.Step 6: Since there is a definite error in the word "of", option D, "None of the above", cannot be correct.Step 7: Conclude that "of" is the problematic part and the sentence should be corrected to "She went to the gym despite her illness."

Verification / Alternative check:
To verify, compare similar sentences: "Despite the rain, they played outside" and "In spite of the rain, they played outside". Both are correct, but "despite of the rain" is not. You can also test the sentence by reading it without "of": "She went to gym despite her illness" already sounds more natural, and adding "the" before "gym" improves it further. This confirms that "of" is the unnecessary word causing ungrammatical usage.

Why Other Options Are Wrong:
The word "to" is used as a basic preposition of direction and does not break any rules here. While some examiners might prefer "to the gym", the lack of "the" is more a matter of style than a clear grammar test point. The word "despite" is correct and used appropriately as a preposition indicating contrast. The noun "gym" correctly names the place she went. Because there is a definite misuse of "of" after "despite", the option "None of the above" is also wrong.

Common Pitfalls:
A common mistake among learners is to mix up "despite" and "in spite of". Since "in spite of" contains "of", they may incorrectly carry this pattern into "despite" and write "despite of". To avoid this, remember that you have two correct patterns: "despite something" and "in spite of something". If you choose "despite", do not add "of"; if you choose "in spite of", always keep "of". Repeating and practising these correct combinations will help you quickly recognise and correct this frequent exam error.

Final Answer:
The grammatically incorrect part of the sentence is of.