The answer would be C, as it is the only one that makes sense when you read it. Hope this helps.
1) C
A - them is unnecessary in this and you would need to add “his” in order for this to work
B- His is unnecessary, “both sisters are taller” is more proper sounding
D - “the two both his sisters are taller”, the two is unnecessary, and the is unnecessary, to make this work it would be “both his sisters are taller”
2) Im pretty sure it’s B but I’m not 100% sure
