Which of the following expression represent Bio-savart law

Options

A. A. `vec dB = (mu_0 I(vec dl × vec r))/(4π(abs(r)^(2)))`
B. B. `vec dB = (mu_0 I(vec dl × hat r))/(4π(abs(r)^(3)))`
C. C. `vec dB = (mu_0 I(vec dl × vec r))/(4π(abs(r)^(3)))`
D. D. `vec dB = (mu_0 I(vec dl . vec r))/(4π(abs(r)^(2)))`