This yellow, round pill imprinted with Sankyo C12 is a Benicar 5 MG Oral Tablet, per the NIH.
Benicar is a human prescription drug. The active pharmaceutical ingredient is olmesartan medoxomil and is classified as, "Angiotensin 2 Receptor Antagonists [MoA], Angiotensin 2 Receptor Blocker [EPC]."
This pill is made by a total of 2 firms: (1) Daiichi Sankyo, and (2) Daiichi Sankyo, Inc.
There are 2 other yellow pills that with a similar imprint: "Sankyo C12". They may be a different dosage of the same drug or a different drug entirely.