Which is correct of Boolean type?

Boolean variables stored as single bits are very space efficient.

The access to a Boolean variable stored as single bit is very fast.

On many machines,$$ access to Boolean variables stored as single bits is slower$$ than if they were stored as bytes.$$

Question options:

Only $1$ is correct

Only $1$ and $2$ are correct

Only $1$ and $3$ are correct

Only $3$ is correct