The prime factorization of 630 is 2 × 3² × 5 × 7.
To find the prime factorization of 630, we need to express it as a product of its prime factors. The prime factorization of 630 is 2 × 3² × 5 × 7. Therefore, option d) 3² × 7 is part of the prime factorization of 630.