Which is right and why

Space heaters heat small areas by use of electric power. Electric current deposits 1500 W of power that goes directly into heat in a filament. Some heaters have a reflector behind the filament, and some also have an internal fan. In the heater to the right, the filament is the glowing vertical thing in the center. The filament heats up until the rate of energy going in equals the rate of energy going out. This balance is what determines the temperature of the filament. A 14. The reflector improves the heat transfer by (A) convection (B) conduction (C) radiation. + 3 C A 15. The fan improves the heat transfer by (A) convection (R) conduction (C) radiation. C 16. Suppose the bottom of the heater is getting too hot. To lower the heat loss to 1/4 its original value, you could increase the thickness (A) 2 times (B) 4 times (C) 16 times +0 B 17. In order to get the filament to the highest possible temperature without melting, what could you say about the latent heat of melting of the filament? (A) It should be large (B) It should be small (C) It doesn't matter. + 4 B 18 In order to get the filament to the highest possible temperature, what could you say about the specific heat of the filament? (A) It should be large (B) It should be small (C) It doesn't matter