List of top Computer Science and IT Engineering Questions on Relational Algebra

Consider a relational database schema with two relations 𝑅(𝑃, 𝑄) and 𝑆(𝑋, 𝑌).
Let 𝐸 = {⟨𝑢⟩∣∃𝑣 ∃𝑤 ⟨𝑢, 𝑣⟩∈𝑅 ∧ ⟨𝑣, 𝑤⟩ ∈𝑆} be a tuple relational calculus
expression.
Which one of the following relational algebraic expressions is equivalent to 𝐸 ?