The answer is correct in this case. In some questions, the code is written as for (let something of obj).
In that case, the answer should be: “An error will occur due to the incorrect usage of the for...of statement on line 07.”

And also object type is only available to declare with 'of', but array type is available to declare either 'of' and 'in'

let obj ={
foo: 1,
bar: 2
}
let output =[];
for(let something in obj){
output.push(something);
}
console.log(output);

Output : [ 'foo', 'bar' ]

watch out.
for(let something in obj) if obj is Json
for(let something of obj) if obj is array