Edwin Ng, Fiona Chan and Samantha Lee are the only directors and equal shareholders of ES Limited. XY Limited is the wholly owned subsidiary of ES Limited and Edwin and Fiona are the directors of XY Limited. Edwin and Fiona just got married in December 2019. Aaron Ho is the auditor of ES Limited. Based on the above information,

assuming that XY Limited has created a charge over its book debts to secure the loan from Fiona in September 2018, before the liquidation of XY Limited in March 2020, (a) evaluate the possible nature of the above charge; and (b) discuss TWO possibilities that Fiona might be ranked as 'unsecured creditor' by the liquidator based on the legal principles of Company Law.