My answer: 1@AB, 2@AC, 3@DC, 4@CC, 5@DB, 6@DA, 7@EC
I chose Black 1 @ AB since Black threatens to connect out. White plays @ AC to prevent it. Black 3 puts the 4 Whites into atari. White 4 connects. Black 5 extends to the 2nd line. White 6 @ EC is not an option due to shortage of liberties, so White plays @ DA to atari the 2 Blacks. Black 7 at EC puts 4 Whites into atari.
Another answer: 1@AB, 2@AC, 3@DB, 4@DC, 5@EC, 6@DA, 7@BB, 8@CC, 9@BA
White 4 @ EC will result in two White groups in atari once Black plays at DC, so White plays at DC. Double atari after Black 5. White captures @ DA. Atari on 2 White stones with Black 7. White 8 is at CC to connect. After Black 9 White group cannot atari 3 Black stones in the corner due to shortage of liberties.