The correct option is B [−3π2,π2]
It is known that
sin−1x+cos−1x=π2
cos−1x=π2−sin−1x
Therefore
sin−1x−cos−1x
=sin−1x−(π2−sin−1x)
=2sin−1x−π2
Now the range of sin−1x is [−π2,π2]
Therefore, the range of 2sin−1x is [−π,π]
Hence the range of 2sin−1x−π2 will be
[−π−π2,π−π2]
=[−3π2,π2]