AT&T has responded to the formal announcement of the CDMA-compliant iPhone 4 for Verizon Wireless, which has also issued a response to AT&T’s statement. Speaking with the Washington Post, AT&T spokesman Mark Siegel downplayed the announcement, saying, “For iPhone users who want the fastest speeds, the ability to talk and use apps at the same time and unsurpassed global coverage, the only choice is AT&T.” Verizon responded…