Iranians go to the polls on May 19 to choose a president. But how much choice does the election really offer?

U.S. President Barack Obama has praised the nuclear deal with Iran, saying it will prevent the spread of nuclear weapons in the Middle East. Speaking in the White House, he said it made the world "safer and more secure." He also said the deal was based not only on trust, but also on a system of verification to make sure that Iran stood by its commitments. (Reuters)