The state of the book is:

Suppose at $9\mathrm{.}46,$ Amy submits an order, "Buy $400,$ limit $10\mathrm{.}05."$ Then

A$.$ Amy buys $200$ from Lucas at $10\mathrm{.}05$; Amy buys $200$ from Adam at $10\mathrm{.}05$; Now, the best bid and offer in the market are: $10\mathrm{.}03$ bid for $400($Ellen$),100$ offered at $10\mathrm{.}05($Adam$).$

B$.$ Amy buys $200$ from Lucas at $10\mathrm{.}05$; Amy buys $200$ from Adam at $10\mathrm{.}05$; Now, the best bid and offer in the market are: $10\mathrm{.}02$ bid for $300($Ada$),100$ offered at $10\mathrm{.}09($Will$).$

C$.$ Amy buys $200$ from Lucas at $10\mathrm{.}05$; Amy buys $200$ from Adam at $10\mathrm{.}05$; Now, the best bid and offer in the market are: $10\mathrm{.}02$ bid for $300($Ada$),100$ offered at $10\mathrm{.}05($Adam$).$

D$.$ Amy buys $200$ from Lucas at $10\mathrm{.}05$; Amy buys $200$ from Adam at $10\mathrm{.}05$; Now, the best bid and offer in the market are: $10\mathrm{.}03$ bid for $400($Ellen$),100$ offered at $10\mathrm{.}09($Will$).$