The smart pen can typically do the following:
a) Write in multiple colors - This may depend on the specific model, as some smart pens are designed to only use one color of ink.
b) Record audio - Many smart pens have this feature, allowing them to record audio while you take notes.
c) Translate text in real-time - Some advanced smart pens may have this capability, although it is not a common feature across all models.
d) Sync handwritten notes digitally - Most smart pens are designed specifically to digitize handwritten notes and sync them with devices.
In summary, options b) and d) are the most commonly associated features of smart pens, while a) and c) may vary depending on the model.