Correct Option: A

Considering the languages L₁ = φ and L₂ = {a}
For all languages L it is known that φ . L = φ
Suppose, ∃ a string s ∈ φ .L
∃ s' such that s = s'. s"
and s ' ∈ φ s" ∈ L
But s ' ∈ φ ∵ φ is an empty language.
∴ φ. L = φ
{ε} ⊆ L* for all languages L.
As it means taking letters from the language and concatenating them ' 0 ' times creating a ' 0 ' length string which is possible for all languages.
∴ ε is in φ*
L₁. L₂ = φ
and L₁ = {ε}
L₁. L₂ * ∪ L *₁ = (L₁. L₂) ∪ L *₁
∴ φ ∪ {ε} = {ε}