[单选题]
A microscope has an objective lens -)e rce*s0t xxof focal length t5bach- up spi ff7h :gv3r7q.b7f4s ;1.4 mm and an eyepiece of focal length 20 mm, adjusted for minimum eyestrain. A blood sample is ps v ba3f7s4;fpgrtq7p75cb.hu -h:f ilaced 1.5 mm from the objective. What is the overall magnification?
