Step 1: Identify major export categories.
India's export portfolio includes textiles, IT services, gems and jewellery, and leather, with varying contributions.
Step 2: Determine the highest export.
Historically, gems and jewellery have been among India's top exports, often surpassing others in value, especially in recent years.
Step 3: Eliminate distractors.
(A) Textile goods - Significant but not the highest.
(B) Jute - Declining export share.
(C) IT services - Growing but not the top.
(E) Leather - Important but lower than gems.
Therefore: The correct answer is (D). \[
\boxed{\text{D}}
\]