Correct Answer: A, B, and C
When you convert leads, Salesforce creates accounts, contacts, and, opportunities using information from the leads you’re converting. Salesforce moves any campaign members to the new contacts, and the leads become read-only records. If existing accounts and contacts share the names specified on the leads, you can choose to update the existing accounts and contacts. Salesforce adds information from the lead into empty fields; Salesforce does not overwrite existing account and contact data. When you convert qualified leads, Salesforce moves any campaign members to the new contacts. The leads become read-only records unless your administrator gives you permission to edit them. If existing accounts and contacts share the names specified on the leads, you can choose to update the existing accounts and contacts. Salesforce adds information from the lead into empty fields; Salesforce does not overwrite existing account and contact data.
Option D is incorrect because all open and closed activities from the leads are attached to the accounts, contacts, and opportunities, except for activities initiated from a High-Velocity Sales cadence. You can assign the owners of these new records, and schedule follow-up tasks.So, Salesforce allows you to create a task related to the activity with due date information and other information based on your custom and standard fields.
Reference:
https://help.salesforce.com/articleView?id=leads_notes.htm&type=5