Each set can be identified by means of a single common featue. List the feature.

{ t, n, l }
{ Ɛ, o, e }
{ Ɛ, g, j }

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The first set is alveolar, and the second set comprises mid vowels. But I can't find the common feature of the third set, since it has both vowels and consonants. Any help would be greatly appreciated!