Answer:
D. There is no mistake.
Step-by-step explanation:
The following lines show the process of factorization by using common factor.
<u>Line 1:</u>
In line 1, the equation is given and is completely fine.

The only thing missing was equate to zero, but the options below talk about correct factors only, therefore this can't be considered as a mistake and can be ignored completely.
<u>Line 2:</u>
In line 2, the terms are grouped, from which we can factor out common terms.

This is also fine.
<u>Line 3:</u>
In line 3, the common term y is taken out from group 1 and 2 from other group.

which is exactly what is given in line 3.
<u>Line 4:</u>
In line 4 the common factors can be seen and easily split into 2 factors.

which is exactly what is given in line 4.
Options:
A. The grouping is correct in line 2. So this option is does not hold.
B. Common factor was factored correctly from group 1. So this option does not hold.
C. Common factor was factored correctly from group 2. So this option does not hold.
D. There is no mistake. This is correct. Thus we choose this option as correct answer.
2,500 yea is that what you were looking for
East common multiple is the smallest multiple both numbers can go into. (Example: the LCM of 10 and 4 is 20, because both 10 and 4 go into 20 and 20 is the smallest number both 10 and 4 can go into. You could just multiply them both, but you'd get 40 and since its a bigger number it would be harder to work with.)
<span>Least common denominator is just the least common multiple as a denominator. (Example: if you wanted to find the LCD of 5/7 and 1/10, you'd have to find the LCM of the demoniators (7 and 10) and then just use that as the denominator when adding fractions with unlikely denominators.) Sorry for such a long answer :P</span>