Which of the following represent isotopes

A
18
39
​
A and
19
39
​
R
B
27
60
​
X and
28
59
​
Y
C
6
12
​
L and
6
14
​
L
D
17
37
​
X and
17
37
​
X
E
2
3
​
E and
1
3
​
G

Correct option is C)