[单选题]
How much energy is necnd ll:g)m h6ng+-o2f jessary tu5 cup cht zfbz:f33(vh5zb x 9b-1i9zo place three charges, each of 2.0 mC, at the corners ofb3 51ix5(3uzfbfb hz 9 vhz-c9t: puzc an equilateral triangle of side 2.0 cm?
A. $4.5 \; J$
B. $5.4 \; J$
C. $6.7 \; J$
D. $7.6 \; J$
