[单选题]
An atomic nucleus has a cdozrrr2n-2 i,s+diodg13 lq 0 nzsk.p-x : 9ofunq9wraju0(in5/ p*vharge of $+40e$. An electron is $10^{-9} \; m$ from the nucleus. What is the force on the electron?
A. $2.9 \; nN$
B. $1000 \; C$
C. $3.7 \; nN$
D. $6.8 \; nN$
E. $9.2 \; nN$