In the following sentence, the bracketed part is grammatically incorrect. Choose the option that best improves the sentence: The purpose of speaking is to communicate, (I chose words that are the best) for the idea I want to convey.

Introduction / Context:
This question tests tense consistency between a general statement of purpose and the clause that explains how that purpose is carried out. The sentence states a general truth about speaking and then describes a habitual action: how a speaker selects words. You must select the option that uses the correct tense and aspect to match that general, timeless context.

Given Data / Assumptions:

• Original sentence: The purpose of speaking is to communicate, "I chose words that are the best" for the idea I want to convey.
• The first clause uses the simple present: "The purpose of speaking is to communicate".
• The writer is describing a general practice or habit, not a single past event.
• The clause that follows the comma must match this general present time frame.

Concept / Approach:
When we state general truths or habitual actions, we use the simple present tense. For example: "I choose my words carefully when I speak." The phrase "I chose" is simple past and refers to a specific time in the past, which does not match the timeless idea of "purpose". Therefore, to make the sentence coherent and grammatically consistent, we need to use "I choose words that are the best". The present simple "choose" aligns with "is" and the ongoing habit described.

Step-by-Step Solution:
Step 1: Identify the main time frame: the sentence describes a general principle about speaking, so it uses the simple present.Step 2: Check the verb in the second clause: "I chose" is in the simple past and is inconsistent with the general present.Step 3: Replace "chose" with the simple present "choose" to express habitual behavior.Step 4: Evaluate option C: "I choose words that are the best". This matches the meaning and tense of the first clause.Step 5: Read the whole sentence to verify: "The purpose of speaking is to communicate, I choose words that are the best for the idea I want to convey."

Verification / Alternative check:
If you test option A, you get "I am choosing words that were the best", which mixes present continuous and past tense without logical reason. Option B, "I did choose words that are the best", sounds like an emphatic past action and is not appropriate for a general statement about purpose. Option D keeps the past tense "chose", which still clashes with the present tense description. Only option C keeps everything in the present and shows a consistent ongoing habit of choosing the best words.

Why Other Options Are Wrong:

• Option A: "I am choosing words that were the best" unnecessarily uses the continuous aspect and then switches to past tense "were", making the time reference confused.
• Option B: "I did choose words that are the best" sounds defensive or emphatic about a past choice and does not match a statement of general principle.
• Option D: "No improvement" keeps "I chose", which is a definite past action and inconsistent with the rest of the sentence.

Common Pitfalls:
A common mistake is to overlook subtle tense shifts, especially when a sentence contains both a broad statement and an example. In exam conditions, many candidates only check whether an individual clause is grammatical and forget to verify that all clauses share a consistent time frame. To avoid this, always identify the dominant tense of the sentence and then ensure that the rest of the sentence matches that tense unless there is a clear reason for a time change.

Final Answer:
The correct improvement is I choose words that are the best.