D. Enable granular locking.

Granular locking is designed to reduce the contention and locking issues that can occur when multiple simultaneous updates are made to sharing rules or group memberships. By enabling granular locking, Salesforce processes these updates in smaller batches or chunks, which significantly reduces the likelihood of locking conflicts. This approach allows for more concurrent updates to sharing settings without causing the severe lock contention that Universal Containers is experiencing.
https://developer.salesforce.com/docs/atlas.en-us.draes.meta/draes/draes_group_membership_locking.htm

C. Enable parallel sharing rule calculation (Option C): Enabling parallel sharing rule calculation allows Salesforce to perform sharing rule calculations concurrently, reducing contention and potential locking issues related to group membership updates. This is particularly helpful when dealing with frequent and persistent locking problems.

Options A (Enable defer sharing calculation) and B (Enable implicit sharing) are not directly related to group membership locking issues.

Option D (Enable granular locking) is not a standard Salesforce feature, and there is no explicit control for enabling or disabling granular locking. Therefore, it’s not a valid option for addressing this specific issue.