The absolute configuration of

is

It is given that when (±)-2,3-dibromobutane reacts with $KOH$, some of the products formed are:

Explain via mechanism and then choose the correct ones from the following.

1. Monosubstitution of (2S,3S)-2,3-dibromobutane using $O{H}^{-}$ yields a mixture of products.

2. Monosubstitution of (2S,3S)-2,3-dibromobutane using $O{H}^{-}$ yields a single major product.

3. Monosubstitution of (2R,3R)-2,3-dibromobutane using $O{H}^{-}$ yields a mixture of products.

4. Monosubstitution of (2S,3S)-2,3-dibromobutane using $O{H}^{-}$ yields a mixture of products.