Which one of the following is the CORRECT expression for Biot-Savart law?

A

$$\oint B.dl = \mu_0 \sum l$$

B

$$\phi_E = \frac{q}{ε_0}$$

C

$$dB \propto \frac{idl \sin \theta}{r^2}$$

D

$$dB = \frac{ir^2 \sin \theta}{dl}$$