Who is the writer of “The Flies”, an adaptation of the Electra myth?

The correct option is Jean-Paul Sartre.

The Flies (French: Les Mouches) is a play written by the renowned French philosopher and writer Jean-Paul Sartre in 1943.
The drama is a modern adaptation of the ancient Greek Electra myth, which was classically dramatized by playwrights such as Aeschylus, Sophocles, and Euripides.

In this adaptation, Sartre uses the mythological characters of Orestes and Electra in their quest to avenge the murder of their father, Agamemnon, by killing their mother Clytemnestra and her lover Aegisthus. Sartre reframes this classic tragedy to reflect his existentialist philosophy, exploring key themes such as human freedom, personal responsibility, and the rejection of guilt imposed by authority (represented by the god Zeus and the symbolic flies).