A: Per the bimi website.

Each participating mailbox provider has their own criteria for determining when a domain’s BIMI logo may be displayed.

There are currently two classes of BIMI records. The simplest is considered to be “self-asserted,” meaning that you publish your logo without it being verified as belonging to your domain. The only requirement for self-asserted BIMI logos is that they be in SVG P/S format. Some mailbox providers accept self-asserted BIMI records today (e.g. Yahoo!, AOL, and Netscape) and may begin to display the logo on qualified messages.

If you left the “a=” attribute blank in the BIMI record, you’ve published a self-asserted logo. Some mailbox providers (e.g. Gmail), however, do not accept a self-asserted BIMI record and require that the logo be “certified” as being associated with a specific company and domain. To address this, there are some organizations that have been authorized to act as Mark Verifying Authorities (MVAs) that vouch for the legitimacy of a proffered logo. These MVAs will verify the association of logos with domains, and issue Verified Mark Certificates (VMCs) that can be added to your BIMI record in the “a=” evidence attribute.

Use the bimi inspector to see check your records - https://bimigroup.org/bimi-generator/

https://bimigroup.org/all-about-bimi/