Given:
The given expression is

We need to determine the equivalent number.
Equivalent expression:
To determine the equivalent number, let us solve the expression

Thus, let us apply the exponent rule
, we get;

Also, the term 10³ can be written as

Thus, we get;

Dividing, we get;
0.001
Hence, the equivalent number is 0.001
Hence, Option c is the correct answer.