why not melt instead of thaw?

[Dongocan]

English Language Proficiency Tests, Advanced Level

ESL/EFL Test #571 "Weather Test (", question 1

In the spring, when the sun shines and warms the earth, the ground begins to ..........

(a) freeze
(b) melt
(c) thaw

English Language Proficiency Tests, Advanced Level

ESL/EFL Test #571 "Weather Test (", answer 1

In the spring, when the sun shines and warms the earth, the ground begins to thaw.

Correct answer: (c) thaw

Your answer was: incorrect
In the spring, when the sun shines and warms the earth, the ground begins to melt.
_________________________

why not melt instead of thaw, please!?many thanks to anyone explaining 4 me!

[Mister Micawber]

.
The snow melts; the ground thaws. Melt = turn to liquid. Thaw = unfreeze.
.
_________________
Native English teacher at Mister Micawber's