Final answer:
The marketer should use the CSV (Comma Separated Values) format to manually upload a list of leads in Marketo.
Step-by-step explanation:
The marketer should use the CSV (Comma Separated Values) format to manually upload a list of leads in Marketo.
CSV is a widely used file format for storing tabular data. It is a plain text format where each line represents a row, and commas are used to separate the values in each column.
Using the CSV format ensures that the lead data is structured correctly and can be easily imported into Marketo.