Which of the following best defines the greatest common factor (GCF) for a list of algebraic terms?

Find the GCF of the integers 84 and 126 using prime factorization.

Given the terms $18x^3{y}^2$ and $24x^2{y}^5$, what is the variable part of the GCF?

Factor completely by extracting the GCF: $14x^3-21x^2+35x$

Factor completely, and show the GCF extraction and the resulting expression: $18x^4{y}^3-12x^2{y}^5+6x^3{y}^2$