Q.What kind of basil is this
I started with 100 seeds but the packet just said basil on it.when I started maybe 40 actually sprouted. Then they all died but one. the leafs look like sweet basil but it doesn’t have a smell to it. It doesn’t taste that sweet either. I taste basil but very mildly.

Certified GKH Gardening Expert
The smaller plants are basil, but that large one is not. It could be one of many solanaceous crops (many of which are toxic, but do include peppers, sunflowers, tomatoes, etc.) or an amaranth.
The smaller plants in that container probably smell stronger, and taste normal. The large plant shouldn't really have a strong smell or taste, since it isn't basil.
As for what kind... That's going to be very difficult. They all resemble each other very closely. It could be one of many, many hybrids, or standard cultivars.
This article will help you to care for the Basil: https://www.gardeningknowhow.com/edible/herbs/basil/how-to-grow-basil-plants.htm