What is the primary difference between $/$dev$/$urandom and $/$dev$/$random$?$

a$./$dev$/$urandom is a PRNG while $/$dev$/$random is a QRNG

b$./$dev$/$urandom uses high entropy while $/$dev$/$random uses low entropy

c$./$dev$/$urandom has a non$-$blocking pool so pseudorandom bits are always available while $/$dev$/$random has a blocking pool so that it can cause a denial of service if the entropy measure is too low

d$./$dev$/$urandom is the PRNG found on UNIX$/$Linux and $/$dev$/$random is the Windows PRNG