Answer:
A
Explanation:
It is formed after the star has ended its star cycle into a supernova. The star collapsed into a neutron star that is smaller than the progenitor star but has inherited angular momentum. IT, therefore, spins faster emitting electromagnetic radiation that seems to pulsate.
F BLOCK is the block on the period table that contains the actinide series of elements.
Actinide series of elements are two rows under the periodic table which include Lanthanide series and Actinide series. These are all radioactive elements and all of these are not not found in nature. All these are included in F block element.
I found this is the order of activity in Internet
Mn>Zn>Cr>Fe>Cd>Co>Ni>Pb
You can see that Fe is between Cr and Cd
Cr is more active than Fe and Fe is more active than Cd.
The Fe will displace Cd but not Cr.
Answer:Fe
