Calibrate what one division means

An unshunted galvanometer of resistance 200 Ω is connected to a stable 1.80 V source through a 1600 Ω series resistor. It deflects by 25 scale divisions.

What is its figure of merit in μA per division?

Organize the givens & assumptions

E = 1.80 V
R = 1600 Ω; G = 200 Ω
θ₀ = 25 divisions

Linear zeroed scale; negligible source resistance; no shunt connected; all resistances constant.

A $45\ \mathrm{\mu A/division}$
B $40\ \mathrm{\mu A/division}$
C $1000\ \mathrm{\mu A/division}$
D $25\ \mathrm{\mu A/division}$

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