Which optical flint glass has the highest mole fraction of zinc oxide? a. Type KF(67%SiO2,16%Na2O,13%PbO,4%ZnO). b. Type LaSF ( 24%La2O3,17%B2O3,15%CdO,11%BaO,8%Ta2O5,7%WO3, 7%SiO2,6%ZrO2,4%ZnO). c. Type BaSF ( 42%SiO2,34%PbO,11%BaO,7%K2O,1%Na2O,5%ZnO)