To find the equivalent expression of (4^-1)^-3, we need to apply the rules of exponents.
First, let's simplify the expression inside the parentheses, which is 4^-1. The exponent -1 means that we need to take the reciprocal of the base. Therefore, 4^-1 is equal to 1/4^1, which is equal to 1/4.
Now we have (1/4)^-3. Applying the rule of negative exponents, we can rewrite this as 1/(1/4)^3.
To simplify further, we need to deal with the reciprocal inside the parentheses. The reciprocal of 1/4 is 4/1, which is equal to 4.
Now we have 1/(4^3). The exponent 3 means that we need to multiply the base (4) by itself three times.
4^3 is equal to 4 × 4 × 4, which is equal to 64.
Finally, we have 1/64.
Therefore, the equivalent expression to (4^-1)^-3 is 1/64.
Hence, the correct option is 4. 1/16.