I would say it is MU going on the roundness of the leaves, but you will be able to tell yourself by comparing two healthy species on the internet.
You can tell the difference by Looking for the leaf detail, roundness, look/ style of the tip where new leaves are being produced, distance between leaves & colour (bacopa can turn red under high light intensity).
Also based on the height it grows, MU only grows to around 15cm. Bacopa, much taller.
MU usually forms a small bush, bacopa isn't quite so neat in its appearance.
Thanks, Aaron