Step 1: Concept
Biodegradable polymers are materials that can be broken down by microorganisms into water, $CO_2$, and biomass.
Step 2: Meaning
Polylactic acid (PLA) is one of the most prominent and widely used biodegradable and bioactive thermoplastic aliphatic polyesters.
Step 3: Analysis
PLA is derived from renewable resources like corn starch or sugarcane and is explicitly used to create biodegradable plastic products like cups, cutlery, and packaging.
Step 4: Conclusion
Therefore, the statement that PLA cannot be used for such products is factually incorrect.
Final Answer: (D)