请教XDF P6 12

Using computer techniques, researchers analyze layers of paint that  lie buried beneath the surface layers of  old paintings. they claim, for example, that additional mountainous scenery once appeared in Leonardo da Vinci's Mona Lisa, which was later painted over. Skeptics reply to these claims, howevere, that X-ray examinations of the Mona Lisa do not show hidden mountains.

whichi of the follwing, if ture, would tend most to weaken the farce of the skeptics' objections?

A. there is no written or anecdotal record that Leonardo Da Vinci ever painted  over major areas of his Mona Lisa.

B. painters of da Vinci's time eommonly created images of mountaionous scenery in the backgrounds of portraits like the Mona Lisa.

C. No one knows for certain what parts of the Mona Lisa may have been painted by da Vinci's assistants rather than by da Vinci himself.

D Infrared photograpgy of the Mona Lisa has revealed no trace of hidden mountainous scenery.

E.Analysis relying on X-ray only has the capacity to detect lead-based white pigments in layers of paint beneath a paininting's surface layers.

答案E

不是很理解这个题目，希望大家帮忙解答一下。