Is $\{\} ∉ A$ true or false, if $A = \{1, 2, 4, a, b, c\}$?

Question

$A = \{1, 2, 4, a, b, c\}$.
$\{\} ∉ A$ (true).
My solution for this question is true. Since $\{\}$ is not an element of $A$. But at college I showed this question to my teacher and he said it is false because $\{\}$ is a subset of $A$ not an element. What's the correct solution for this? PS: Here is the question from the book circled in red.

Answer 1

I preassume that the symbols $1,2,4$ do not denote the empty set.

Then: $$\{\}\notin A\text{ is true if }a\neq\{\}\text{ and }b\neq\{\}\text{ and }c\neq\{\}$$

Otherwise it is false.

If nothing is known about $a,b,c$ then you should state that the statement is not true in general.

Further $\{\}$ is indeed a subset of $A$ but that is not relevant here.

Answer 2

The empty set is a subset of every set.

For the set $A$ In the question , the empty set is not an element of the set.

Answer 3

…he said it is false because $ \{ \} $ is a subset of $ A $ not an element.

If it's, as he said, not an element and "$ \notin $" means "is not an element of", then it's obviously true.