If E Is the Electricity Fraction of the Total Energy

If e is the electricity fraction of the total energy output, m is the electric plant efficiency and n is the steam generator efficiency; the heat added per unit total energy output is given by?

A) (1 / m) + ((1 - e) / n)
B) (1 / n) + ((1 - e) / m)
C) (1 / m) + ((1 + e) / n) .
D) (1 / n) + ((1 - e) / m) .