Interpretation  Go to the MD5 Broken challenge

If I am reading the description right, we have a 128-bit MD5 hash that is created from 7 lowercase ascii letters. The challenge gives us 64 bits. Am I correct to assume that each byte lost either its 4 MSBs or its 4 LSBs?
Is it just any 4 bit indexes that are being omitted per byte?

Or is it really random, in the sense that any 64 bit indexes out of the entire 128 bit hash were omitted?

Quote from WingeDD

Am I correct to assume that each byte lost either its 4 MSBs or its 4 LSBs?

This is correct.

A Nibble of a byte is usually the contiguous 4 high or 4 low bits

Aren't there multiple answers?

Theoretically, yes.
A hash of length 4 bytes can hold up to 2^32 different values (the hash value)
But you can create an infinite amount of different plaintexts.
Of course, like sha512 there are already 2^512 diferent outcomes..
The rest is left as an excercice to the reader.