What Is the Resulting PH If 10 Millimoles of HCl

What is the resulting pH if 10 millimoles of HCl is added to 1 liter of a 0.1 M phosphate buffer at pH 7.00 (pK=6.82) ?

A) 6.82
B) 6.98
C) 7.01
D) 7.19
E) cannot be determined