The "Accordion" Lightning component is designed to break up content into collapsible sections. This component would be suitable for managing the visibility of large numbers of fields by grouping them into separate tabs or sections that can expand and collapse. This makes navigation easier and declutters the interface.
A: Highlights panel is used for displaying key record information at the top of the page and is not designed for managing multiple fields.
B: Record detail displays all fields on a single layout, which does not suit the requirement to break up the fields.
C: Field section does not exist as a standard Lightning component. Reference: Accordion Component in the Lightning Component Library

Email alert, task, and invocable flow are three action types that can be used in an approval process. Email alert can send an email message to one or more recipients. Task can assign a task to a user or queue. Invocable flow can launch a flow that performs complex logic and actions

Changing custom field types may result in data loss if the new field type is incompatible with the old one. For example, changing a text field to a number field may cause text values to be deleted. Field history tracking records value changes of 255 characters or less. If a rich text field value exceeds this limit, only the first 255 characters are tracked.

A: Changing the Lead Matching Rule to 'Block on create' will directly prevent duplicates at the point of lead creation based on defined criteria.
C: Changing the Lead Duplicate Rule to 'Bypass Sharing Rules' allows the system to compare leads across the entire organization regardless of the user's access level, which is crucial especially when OWD is set to 'Private'.
Reference:
Salesforce Help - Duplicate Management