Marc Lijnders operates a licenced bar. During the $2023$ income year, Marc recorded the following trading stock balances $($excluding GST$)$: Trading stock at $30$ June @$022$ $$75000($ at cost$)$ ; Trading stock at $30$ June $2023$ $$95,000($at cost$)$; $$105000($at replacement value$).$ What is the correct treatment to account for Marc's change in trading stock level? a$)$ $$20,000$ assessable income b$)$ $$20,000$ allowable deduction c$)$ $$30,000$ assessable income d$)$ $$30,000$ allowable dedduction