A

Step 1: Understand the significance of a total solar eclipse. During a total solar eclipse, the Moon completely covers the Sun, blocking its bright light for a brief period.
Step 2: Analyze the concept of Fraunhofer lines. Fraunhofer lines are dark lines in the spectrum of sunlight caused by the absorption of specific wavelengths by elements and molecules in the solar atmosphere. These lines are characteristic of the presence of different elements in the Sun.
Step 3: Consider what happens to the solar spectrum during the eclipse. The solar radiation is significantly diminished while the Moon covers the Sun, but the wavelengths that would typically appear as dark Fraunhofer lines are still present as they result from the absorption of light by elements in the solar atmosphere.
Step 4: Evaluate the options. Since the absorption lines are intrinsic to the solar spectrum, even at the time of total eclipse, we would still observe many dark Fraunhofer lines, though their overall brightness would be reduced due to the diminished solar irradiation.
Thus, the correct answer is: A large number of dark Fraunhofer lines.