Number of moles of Fe in 558.5 gm of Fe is

$$ = $$ $${{558.5} \over {55.85}}$$

$$ = $$ 10

$$\therefore$$ Number moles of Fe in 558.5 gm Fe is = 10

Since here Fe is monoatomic then no. of atoms in 10 moles Fe is

$$ \Rightarrow $$ 10 $$\times$$ 1 $$\times$$ N_A

$$ \Rightarrow $$ 10 N_A

For Option (A) Atomic Mass of Carbon is 12 g then no. of moles in 60 g Carbon is

$$ \Rightarrow $$ $${{60} \over {12}} = 5$$

Here Carbon is also monoatomic then no. of atoms in 5 moles of Carbon

$$ \Rightarrow $$ 5 $$\times$$ 1 $$\times$$ N_A

$$ \Rightarrow $$ 5 N_A

Now we can clearly see 10 is twice of 5, so option (A) is correct.