BENGALURU/SAN FRANCISCO: Tesla's quarterly sales plunged 13 percent to the weakest in nearly three years, hurt by a backlash against CEO Elon Musk's politics, rising global competition, and people waiting for a refresh to its highest-selling electric vehicle Model Y. The stumbling sales indicate that the one-time leading brand is reeling from the fallout of the company delaying launches for years, and Musk's foray into politics in the United States and Europe . Tesla shares fell 2 percent in