211.

Which command would you use to list the existing files in the native image cache?

The Native Image Generator (Ngen.exe) is a tool that improves the performance of managed applications. 
Ngen.exe creates native images, which are files containing compiled processor-specific machine code, and installs them into the native image cache on the local computer. 
The runtime can use native images from the cache instead using the just-in-time (JIT) compiler to compile the original assembly.