What infant formula is closest to breast milk?

All try to be: If considering a formula, the primary difference in types is the source of protein, (cow milk vs soy bean) and type of sugar (lactose vs non-lactose). All are regulated a by the fda and required to have certain components. All claim to be similar to breast milk in their benefit to the kids. The major brands are supported by decades of continuing research. Find one baby likes and stick with it.