为了增大LC振荡电路的固有频率，下列方法中可采取的是（　　）

A．增大电容器两极板间的正对面积并在线圈中放入铁芯

B．减小电容器两极板的距离并增加线圈的匝数

C．减小电容器两极板的正对面积并减小线圈的匝数

D．减小电容器两极板的距离并在线圈中放入铁芯

Public protests can cause even the most powerful companies to change their policies. For example, an activist group recently staged a demonstration in front of the HydraBore corporate headquarters to protest the company’s use of the chemical Ectomazathol. Within three months of the demonstration, HydraBore replaced Ectomazathol in its production plants with another chemical.
Which of the following, if true, casts the most doubt on the connection between the public protest and the decision of the company to change chemicals ？（）

A. Preliminary studies show that the new chemical may be more carcinogenic than Ectomazathol.

B. The recently introduced chemical that is replacing Ectomazathol is less expensive and more effective in its industrial application than Ectomazathol.

C. HydraBore devoted no publicity efforts to announce its switch from Ectomazathol to the new chemical.

D. As protests against HydraBore have become more frequent, the company has subsequently increased its public relations budget.

E. The activist group that staged the demonstration has been linked to illegal acts of theft and sabotage within other corporate headquarters.