Question

The boron atom of BBr3 has

one atomic orbital.
two atomic orbitals.
three hybrid orbitals.
four hybrid orbitals.

Answer 1

Boron has three hybrid orbitals that is 2s 
hopefully it helps.

Answer 2

Answer: The boron atom of $BBr_3$ has three hybrid orbitals

Explanation: Hybridization of the molecule can be calculated by:

$Hyb=\frac{1}{2}(V+H-C+A)$     .....(1)

where,

V =  number of valence electrons in the central metal atom

H = number of monovalent atoms

C = cationic charge

A = anionic charge

Here, electronic configuration of B = $1s^22s^22p^1$

Number of valence electrons = 3

Number of monovalent atoms = 3

Cationic charge = 0

Anionic charge = 0

Putting these values in equation 1, we get

$Hyb=\frac{1}{2}(3+3-0+0)=3$

As the Hybridization is 3, which means that boron has 3 hybrid orbitals.