Final answer:
Telescope D, with the longest objective lens focal length of 43 centimeters, would have the greatest magnification among the four telescopes.
Step-by-step explanation:
The student has asked which telescope labeled A, B, C, or D would have the greatest magnification given the focal lengths of their objective lenses. To determine the telescope with the greatest magnification, we must consider the principle that magnification is proportional to the focal length of the objective lens when all telescopes have eyepieces of the same focal length. According to the information provided, to achieve the greatest magnification, a telescope should have a long focal length for the objective and a short focal length for the eyepiece. Telescope D, with a focal length of the objective lens of 43 centimeters, would have the greatest magnification of the four since it has the longest focal length.