Concept:
Quorum is the minimum number of members required to be present to conduct the proceedings of a House. Without quorum, the House cannot continue its business.
• Ensures proper representation.
• Makes the proceedings valid.
• Prevents decisions by very few members.
Step 1: Understand the constitutional provision.
According to Article 100 of the Indian Constitution:
\[
\text{Quorum} = \frac{1}{10} \times \text{Total members}
\]
Step 2: Interpret the meaning.
If the total members of a House are 500:
\[
\frac{1}{10} \times 500 = 50
\]
So at least 50 members must be present.
Step 3: Compare with options.
• One-Tenth -- correct
• Two-Third -- incorrect
• One-Fifth -- incorrect
• One-Sixth -- incorrect
Step 4: Final conclusion.
Hence, the correct answer is:
\[
\boxed{\text{One-Tenth}}
\]