可数名词的疑惑~```making up an unusual trio of trumpet,guitar and d

可数名词的疑惑~
```making up an unusual trio of trumpet,guitar and drums.
1 这个句子中为什么trumpet,guitar用单数而drums是复数呢?
2 我觉得他们应该保持一致啊,他们都是可数名词啊~为什trumpet,guitar既不用复数形式又没有冠词?
3 这样说可以吗?```making up an unusual trio of trumpets,guitars and drums
或者 ```making up an unusual trio of the trumpet,the guitar and the drum
这样说也可以吗？making up an unusual trio of a trumpet,a guitar and drums