Perhaps some case of piger or impiger. We are confident that g is correctly read; it has a remarkably long tail (as does r in this hand).
It is not possible to read do[mine after exoro.
scribti-/[o]ne seems a plausible restoration; for the spelling cf. 339.4. This would suit the context if the reading accus/[a]ntium (in which the first c is re-made) is correct. A noun in the accusative would then follow.
If fragment (c) does not fit below, this piece may belong with a.1.