[单选题]
A compound microscope has z9uv9 ngp(dquk yu106gg. j,t a 18-cm barrel a j4vgf p-)h:vuoa3z3i nd an objective with a focal length of 8.0 mm. What is the foca)f hg3j-3: vi4p azvoul length of the eyepiece to give a total magnification of 240?
A. $0.13 \; cm$
B. $1.5 \; cm$
C. $1.9 \; cm$
D. $2.3 \; cm$
