This yellow, round pill imprinted with B 90 is a 24 HR Nifedipine 90 MG Extended Release Tablet [Nifediac], per the NIH.
Nifediac CC is a human prescription drug. The active pharmaceutical ingredient is nifedipine and is classified as, "Calcium Channel Antagonists [MoA], Dihydropyridine Calcium Channel Blocker [EPC], Dihydropyridines [Chemical/Ingredient]."
This pill is made by a total of 4 firms: (1) Teva Pharmaceuticals USA Inc, (2) State of Florida DOH Central Pharmacy, (3) TEVA PHARMACEUTICALS USA, and (4) Bryant Ranch Prepack.
There are 3 other yellow pills that with a similar imprint: "B 90". They may be a different dosage of the same drug or a different drug entirely.