In the following sentence, identify the part that contains a grammatical error: "Beside, writing is my hobby, / I had ideas for a couple of short stories / that needed further thought."

Introduction / Context:
Error-detection questions check your ability to spot incorrect usage in sentences that otherwise look natural. Here the sentence talks about writing as a hobby and having ideas for short stories. The main issue is with the use of the word "Beside" at the beginning, which is a common confusion in English between "beside" and "besides". Understanding the difference between these two similar-looking words is essential for avoiding such errors.

Given Data / Assumptions:
- The sentence is split into three parts labelled A, B, and C, plus a "No Error" option.
- Part A: "Beside, writing is my hobby,"
- Part B: "I had ideas for a couple of short stories"
- Part C: "that needed further thought."
- We must choose the part that contains the grammatical or usage error.

Concept / Approach:
"Beside" and "besides" have different meanings. "Beside" usually refers to physical position, meaning "next to", as in "She sat beside me." "Besides", on the other hand, is used as a preposition or adverb meaning "in addition to" or "as well as", as in "Besides writing, I enjoy painting." In the given sentence, the intended meaning is "in addition to other things, writing is my hobby", so "besides" is the correct choice, not "beside". Therefore, the error lies in part A.

Step-by-Step Solution:
Step 1: Read the complete sentence for overall sense: the speaker is talking about writing as a hobby and having ideas that need more thought.
Step 2: Focus on the first word "Beside". Check its usual meaning of "next to" a person or thing.
Step 3: Ask yourself whether "next to" fits here: "Next to, writing is my hobby" clearly does not make sense.
Step 4: Recognise that the intended meaning is "in addition to other things", for which the correct word is "Besides". Therefore, part A is incorrect.

Verification / Alternative check:
If we correct the sentence to "Besides, writing is my hobby, I had ideas for a couple of short stories that needed further thought", the meaning becomes clearer, although the sentence would still be better broken into two separate sentences or clauses. Parts B and C, however, are grammatically acceptable as written: "I had ideas for a couple of short stories" and "that needed further thought" both make sense and are correctly constructed relative clauses and noun phrases.

Why Other Options Are Wrong:
- Part B: "I had ideas for a couple of short stories" is a correct and natural phrase.

- Part C: "that needed further thought" correctly describes the stories and is grammatically fine.
- Part D: "No Error" cannot be chosen because we have already identified a clear usage mistake in part A.

Common Pitfalls:
Many learners misuse "beside" and "besides" because they sound similar. To avoid this, remember: "beside" (without s) is mostly about physical position (next to), while "besides" (with s) is about addition (in addition to, moreover). Keeping this distinction in mind will help you quickly identify and correct such errors in exam sentences.

Final Answer:
The error is in part A; it should use "Besides" instead of "Beside".