9.67Level 16 — melodic line through both

Over D7 → G7 → C:

try:

F♯ → F → E

or:

C → B → B.

Over D7 → D♭7 → C:

try:

F♯ → F → E

again.

Interesting:

the same chromatic upper line can support very different bass/harmonic routes.

That is advanced voice-leading thinking.