According to EMA Variation Guideline, what type of variation is required to be notified immediately upon implementation?

The correct choice pertains to Type 1A in the context of the EMA Variation Guideline. This type of variation includes changes that are considered to be of a minor nature but require immediate notification upon implementation.

Type 1A variations generally refer to changes that do not affect the quality, safety, or efficacy of the medicinal product but involve important updates that need to be documented. These can include changes in the address of the marketing authorization holder or minor administrative updates. The regulatory framework emphasizes the necessity for immediate notification to ensure that the agency is kept informed of even the minor changes, which can be crucial for maintaining accurate and current records.

In contrast, Type 1B and Type 2A variations are associated with other categories of changes that either require more detailed assessment or are of a different significance regarding impact on product characteristics. Type 3 variations typically involve major changes that require a full review process prior to implementation, and thus do not have the same immediate reporting requirement as Type 1A variations.