MP3's

Kilobits.

a) From context
b) Pedantically, it has to have an uppercase 'B' to be 'bytes' (i.e. kB/s as opposed to kb/s)

cheers

In fact it's 1024 bits per second, as they are using a transformation that requires data to be transformed in blocks of 2^q size. (for this reason you have bit rates 128 kbps, and 256 kbps in audio streams. 194 kbps is either done in three 8 * 1024 byte blocks, or in one 32 * 1024 byte block where least important bytes are filled by zeroes.)