Whichofthefollowingistrueaccordingtoparagraph3and4?______( )
A.Thewriterintroducesmethodsofprovidingpowerdensity. B.Thewriterintendstodescribeanuclear-poweredsystem. C.Thewriterintroducesnuclearbatteriescanbesafelyused. D.Thewriterislikelytoshowchemicalbatteriesarewidelyapplied.正确答案C