Step 1: Recall the structure of Rajya Sabha.
Rajya Sabha is a permanent upper house - it cannot be dissolved; members serve 6-year terms, and retirement is staggered so the chamber retains experienced members and institutional continuity at all times.
Step 2: Identify the retirement cycle under Article 80.
Article 80 of the Constitution provides for staggered retirement: one-third of Rajya Sabha members retire every 2 years; this means elections for roughly 80 seats are held every 2 years across the country.
Step 3: Confirm the arithmetic and answer.
With 6-year terms and 1/3 retiring every 2 years, exactly three cycles of 2 years cover all members within one full 6-year tenure; the answer is 2 years, making option (1) correct.
\[ \boxed{2 \text{ years}} \]