Option D is correct.
Step-by-step explanation:
Given the work of Ryan to find the greatest common factor of 48 and 72
Prime factorization of 48: 2, 2, 2, 2, 3
Prime factorization of 72: 2, 2, 2, 3, 3
Ryan find the GCD as
Ryan error is he take the prime prime factor with largest exponent which is done to find the LCM i.e least common multiple
Hence, Ryan mistake is that he found the least common multiple
Option D is correct.