Solve the Formula for the Indicated Variable $\mathrm { R } = \mathrm { nE } - \mathrm { nr }$

Multiple Choice

Solve the formula for the indicated variable.
- $\mathrm { R } = \mathrm { nE } - \mathrm { nr }$ , for $\mathrm { n }$

A) $n = \frac { R } { E - r }$
B) $n = R - E + r$
C) $n = R + n r - E$
D) $n = \frac { R + n r } { E }$