The correct option is B 920:1528:27
P:Q=35:57=(21:25)×3=63:75
Q:R=34:25=(15:8)×5=75:40
P:Q:R=63:75:40
Let us check options one by one.
(a) (35:57:25)×35[LCM of 5,7,5 is 35]
21:25:14 [not correct]
(b) (920:1528:27)×140 [LCM of 20,28,7 is 140]
=63:75:40
This matches what we obtained above.
Hence option (b) is correct.