Identify the part which contains an error.
He is / suffering from / pneumonia / for a week now.

Correct option is A

Option (a) contains an error.
Detailed Explanation of Error:
The sentence uses Present Continuous tense: “He is suffering”.
However, the time expression “for a week now” denotes a duration that started in the past and continues till the present. This requires the Present Perfect Continuous tense, not the Present Continuous tense.
The correct structure should be:
He has been suffering from pneumonia for a week now.
Hence, the error lies in part (d) because it mismatches with the tense used earlier in the sentence.
Grammatical Rule Used:
· Present Perfect Continuous Tense is used for actions that began in the past and are still continuing.
· Structure:
Subject + has/have + been + verb (-ing) + since/for
Example:
She has been preparing for the exam for two months.
Information Booster / Exception:
· Expressions like since, for, lately, recently, for a long time generally demand Perfect Continuous Tense, not Present Continuous.