______ his timely help, Kate overcame the hardship at last.                                                                                                                                                                                                                                                                                                                                                                                                                         

A．Now that

B．Thanks to

C．Since

D．Because

氯化钠的溶解度为36g,该温度下氯化钠溶液中溶质的质量分数不可能为（）

A．20%

B．26.5%

C．25%

D．30%