JOHANNESBURG (Reuters) - South Africa s ruling African National Congress formally nominated Deputy President Cyril Ramaphosa and former cabinet minister Nkosazana Dlamini-Zuma as the only candidates to run for the presidency of the party at a conference on Sunday. The official nominations, announced by an election official, come after months of campaigning across Africa s most industrialized economy set the stage for the start of voting by 4,776 delegates in the tight race between the two candidates. 