Starting from right for the number 9578,

Place value of 8 is ones = 8× 1

Place value of 7 is tens = 7× 10

Place value of 5 is hundred = 5× 100

Place value of 9 is thousand = 9× 1000

Hence, expanding form of the number is adding all above,

i.e. 9 × 1000 + 5 × 100 + 7 × 10 + 8 × 1

Hence, (C) is the answer.