[单选题]
An electron is held up against tl b0zx 1ohkz/vu0 c*j;ya5o*o he force of j1n94*ted vq 9hs6s efgravity by the attraction of a fixed proton some distance above it. How far above the electron 4j9* nvfh16dqestse 9 is the proton?
A. $1.5 \; m$
B. $2.3 \; m$
C. $3.7 \; m$
D. $5.1 \; m$
