The set of symbols that represents isotopes has been 84/38 M 86/38 M 87/38 M. Thus, option D is correct.
The isotopes are the elements with same atomic number, but different mass number. In an isotope [tex]\rm ^a_bX[/tex], a has been the atomic mass, and b has been the atomic number.
The isotopes will have same value for b, while different values for a.
In the following given sets:
A. 50/19 L 50/20 L 50/21 L
It has same number of mass the atomic number has been different. Thus, the set not represents isotopes.
B. 138/59 Q 133/55 Q 133/54 Q
The given elements, has different atomic number, and different mass number. Thus the set did not represents the isotopes.
C. 91/42 J 92/42 J 93/40 J
The given elements, has different atomic number, and different mass number.Thus the set did not represents the isotopes.
D. 84/38 M 86/38 M 87/38 M
The given set has same atomic number with different mass number.Thus, the set has been the representation of isotopes.
The set of symbols that represents isotopes has been 84/38 M 86/38 M 87/38 M. Thus, option D is correct.
For more information about isotopes, refer to the link:
https://brainly.com/question/13214440