Answer:
The correct answer out of the four given options is
option a. light elements with atomic numbers less than 5
Explanation:
Big Bang nucleosynthesis, abbreviated as BBN, also known as primordial nucleosynthesis took place after the Big Bang for about 10 s to 20 minutes and resulted in the yield of isotopes of helium-4 ([tex]^{4}He[/tex]), helium-3 ([tex]^{3}He[/tex]) which accounts for most of the world's helium, other isotopes of hydrogen in small amounts like deuterium (D or[tex]^{2}H[/tex]) and lithium isotope, lithium-7([tex]^{7}Li[/tex]) in small amount.
Apart from these stable nuclei, it also yielded two radio-active isotopes: tritium([tex]^{3}H[/tex]) and beryllium-7([tex]^{7}Be[/tex]) which due to their unstability later decayed into ([tex]^{7}Li[/tex]) and ([tex]^{3}He[/tex]).
All of these isotopes are of light elements with atomic number less than 5.
