Question 841393
The student has used confusing set notation.
You use commas to separate the elements. 
Additionally, the curly brackets denotes the collection of elements in the set. 
Adding another set of curly brackets only causes confusion. 
If the student wants to denote a set of other sets, you would write.
A={B,C,D} where B={1},C={0,1}, and D={1,2} are other sets, you wouldn't write
A={{1},{0,1},{1,2}}
So if that was the students intent, she would write A={1,B}