During strenuous exercise, lactic acid builds up in muscle tissues. In a 1.00 M aqueous solution, 2.94% of lactic acid is ionized. What is the value of its Ka?

A. 1.20 x 10⁻⁴
B. 2.94 x 10⁻²
C. 5.00 x 10⁻⁵
D. 7.14 x 10⁻³