Math---probability1

the possible combination of Lock A
= 40 x 40 x 40
= 64000

the possible combination of Lock B
= 9 x 1 x 78 x 77
= 54054
(since all prime number from 1 to 80/3 are 2, 3, 5, 7, 11, 13, 17, 19, 23)

the possible combination of Lock C
= 2 x 10 x 9 x 8 x 7 x 6
= 60480

thus you should buy Lock C

Lonely lonely Christmas~~~
Merry merry Christmas~~~