In 1800, nearly 25 years after
his discovering of methane gas, Alessandro Volta, the Italian physicist, had developed what would become known as the voltaic pile, the first electric battery.
(A) his discovering of methane gas, Alessandro Volta, the Italian physicist, had developed what would become known as the voltaic pile, the first electric battery
(B) his having discovered methane gas, Alessandro Volta, the Italian physicist, developed the first electric battery, which will later become known as the voltaic pile
(C) his discovery of methane gas, Italian physicist Alessandro Volta developed the first electric battery, later known as the voltaic pile
(D) discovered methane gas, Italian physicist Alessandro Volta's discovery of the first electric battery, later known as the voltaic pile
(E) his discovery of methane gas, Alessandro Volta was an Italian physicist who developed the first electric battery, which would later be known as the voltaic pile