Given the formula for compound interest A = P(1 + r/n)^nt, isolate r symbolically (write r in terms of A, P, n, and t).

• A. r = (A / P)^{n / t} - n
• B. r = (A - P) / (Pnt)
• C. r = (A / P)^nt - 1
• D. r = n[(A / P)^{1 / (nt)} - 1]