根据对话内容，从对话后的选项中选出能填入空白处的最佳选项

Mike: May I use your car, Jane?

Jane: Yes, of course, __________

Mike: Just one or two hours.

Jane: OK. __________ By the way, _________

Mike: I’m going to the train station to meet a friend

of mine.

Jane: Can you do something for me?

Mike: ___________

Jane: Will you buy some apples for me on your way?

Mike: _____________

某同学看到学校花圃的花草生长不好，经查看有关资料知道,这些花草应该在弱碱性环境中生长，该同学对花圃的土壤进行化学分析，结果发现该土壤配成的溶液使石蕊由紫色变成红色，则为改良土壤最适宜选择的物质是 [ ]

A．氯化钾

B．纯碱

C．氢氧化钠

D．熟石灰