[单选题]
A microscope has an objectifzadpy g878 n0ve lel-e y51p sz4rv,ioft /ns of focal length 1.4 mm and an eyepiece of focal length 20 mm, adju5- lsr1pyfe,z4oi tv/sted for minimum eyestrain. A blood sample is placed 1.5 mm from the objective. What is the overall magnification?
