Which instrument came first?

Answer 1

My guess is that it would be a drum, or other percussion instrument. They would have been very low tech and rudimentary.

The following quote from WikiPedia tends to reinforce my thoughts.

"Anthropologists and historians often speculate that percussion instruments were the first musical devices ever created. The human voice was probably the first musical instrument, but percussion instruments such as hands and feet, then sticks, rocks, and logs were almost certainly the next steps in the evolution of music.

The earliest percussion instruments were our hands and feet, then "found" objects such as sticks, logs, and hips. As human communities developed tools for hunting and eventually agriculture, their skill and technology enabled them to craft more complex instruments. For example, a simple log may have been carved to produce louder tones (a log drum) and instruments may have been combined to produce multiple tones (as in a 'set' of log drums)."