[单选题]
A metal sphere of radius 2.0 cm carries a chargy6aw rf cfbe(2):t.ene of 3.0 mC. What is the el.st-fz l40rsgectric field 6.0 cm from the center of the spheret0gfs4sr -l. z?
A. $4.2 \times 10^{6} \; N/C$
B. $5.7 \times 10^{6} \; N/C$
C. $7.5 \times 10^{6} \; N/C$
D. $9.3 \times 10^{6} \; N/C$