The best way to write comments for the given code would be:
# Calculate price with tax
# parameter price: numeric
# parameter rate: tax rate
# NOTE: for tax of 8.5% rate should be 8.5, not 0.085
This option is concise and clearly explains what the function does, as well as providing details about the parameters and an important note regarding the tax rate. It maintains clarity and relevance without unnecessary verbosity.