Read the following sentence and identify the part that contains an error in standard English usage, or mark No error if the sentence is correct: "I am glad that you are here."

Introduction / Context:
In this error spotting question you must decide whether the sentence "I am glad that you are here." contains any grammatical or usage error. Often, exams include some perfectly correct sentences to check whether candidates can distinguish false errors from real ones. It is important not to over correct a sentence that is already standard and natural.

Given Data / Assumptions:
The sentence is broken into parts as follows:
- Part (a): "I am"
- Part (b): "glad"
- Part (c): "that you are here."
- Part (d): "No error"
The task is to identify which part, if any, is incorrect in terms of grammar or standard English usage.

Concept / Approach:
The expression "I am glad that you are here" is a normal and polite English sentence. The linking verb "am" correctly connects the subject "I" to the predicative adjective "glad". The clause "that you are here" functions as a noun clause explaining the cause of the speaker's gladness. There is no tense mismatch, no preposition error, and no word order problem. Therefore, the sentence is fully acceptable as it stands.

Step-by-Step Solution:
Step 1: Check subject verb agreement in part (a). The subject "I" takes the first person singular form "am", which is correct. Step 2: Check the use of the adjective "glad" in part (b). It is correctly placed after the linking verb "am". Step 3: Examine the clause "that you are here" in part (c). It states a present situation and uses the present tense "are" correctly. Step 4: Confirm that punctuation and word order are normal for conversational English. Step 5: Since no part contains an error, select "No error" as the correct answer.

Verification / Alternative check:
Try replacing the sentence with other well known patterns: "I am happy that you are here", "I am surprised that you are here". All of these follow the same structure and are accepted without question. There is no hidden rule that prohibits "that" after "glad". In fact, both "I am glad you are here" and "I am glad that you are here" are widely used.

Why Other Options Are Wrong:
- Part (a): "I am" is correct in both grammar and usage.
- Part (b): "glad" is the appropriate adjective to express happiness or satisfaction.
- Part (c): "that you are here." is a properly formed subordinate clause explaining the cause of the emotion.
Thus none of these parts contains an error, so choosing any of them would be incorrect.

Common Pitfalls:
Some students feel compelled to find an error in every question and therefore question correct structures such as "glad that", "happy that", or "afraid that". Remember that in error spotting sections, some sentences are intentionally error free. It is a good practice to first ask whether a sentence sounds natural and matches structures you have seen in good sources. If it clearly does, you should confidently mark "No error".

Final Answer:
The sentence is correct, so the right choice is No error, that is, part (d).