The correct Biot-Savart law in vector form is

Concept-

Biot-Savart Law:

• The law who gives the magnetic field generated by a constant electric current is Biot-savart law.
• Let us take a current carrying wire of current I and we need to find the magnetic field at a distance r from the wire then it is given by:

 = magnetic field due to current carrying wire element dl at the point

Where,

μ₀ = the permeability of free space/vacuum (4π × 10-7 T.m/A),

dl = small element of wire

= the unit position vector of the point where we need to find the magnetic field.

Explanation-

It is the vector form of the Biot-savart law. So option 2 is correct.