The statements regarding data type conversions and the treatment of literals in SQL expressions involve understanding implicit and explicit data conversions in Oracle SQL.
Statement A is true as invoice_date > '01-02-2019' involves an implicit conversion of the string literal to a date type, based on the NLS_DATE_FORMAT setting, assuming the format matches.
Statement E is true because, similarly to A, invoice_date = '15-march-2019' involves an implicit conversion where the string is automatically converted to a date type according to the Oracle NLS_DATE_FORMAT or an assumed default date format.
Statements B, C, and D involve incorrect or misleading information:
B (qty_sold = '05549821') is misleading and potentially incorrect as leading zeros in a numeric context do not typically require explicit conversion but the presence of spaces might suggest a need for trimming rather than numeric conversion.
C (CONCAT(qty_sold, invoice_date)) would indeed require explicit conversion because CONCAT expects string types, and thus numerical and date values must be explicitly converted to strings before concatenation.
D (qty_sold BETWEEN '101' AND '110') uses implicit conversion where the string literals '101' and '110' are implicitly converted to numbers if qty_sold is a numeric type.