Explanation

Option B is correct because the frequency of index tracking itself is not a source of tracking error. Most ETFs track their indices on a continuous basis throughout the trading day, and this frequency doesn't inherently create tracking error.

Option A is incorrect because representative sampling (holding only a subset of index securities) is a common source of tracking error.

Option C is incorrect because holding depositary receipts instead of actual index constituents can create tracking error due to differences in pricing, liquidity, or other factors between the receipts and the underlying securities.