A sample of solid candle wax is put into a pot on the stove. Heat energy is transferred to the wax at a constant rate by the burner on the stove. Match the segments on the graph to the correct description of what is happening to the wax. A-B

B-C

C-D

D-E

E-F

(match them)
melting
gasseous wax heating
solid wax heating
boiling
liquid wax heating

Explanation:

The temperature increases as each phase is heating. The temperature remains constant as each phase is changing to the next. The phases associated with increasing temperature are solid, liquid, gas — in that order.

A-B  solid wax heating

B-C  melting

C-D  liquid wax heating

D-E  boiling

E-F  gaseous wax heating

i think it's letter a.