रमेश जगदीश का भाई है।
Step 1: Meaning of the sentence.
"रमेश जगदीश का भाई है।" means "Ramesh is Jagdish's brother."
Step 2: Checking options.
(A) Wrong — implies both have brothers.
(B) Wrong — past tense ("was") is incorrect.
(C) Wrong — word arrangement is awkward.
(D) Correct — directly matches the sentence.
Step 3: Conclusion.
Correct translation is Ramesh is Jagdish's brother.
मैं एक पत्र लिखने जा रहा हूँ।