Sponsored by Alex Nichols Agency GUARANA RETURNS AT CHURCHILL 8th-CD, $85K, Opt. Clm. ($80K), 3yo/up, f/m, 7f, 4:46p.m. Dual Grade I winner and 'TDN Rising Star' GUARANA (Ghostzapper) makes her seasonal bow Thursday beneath the Twin Spires. Demolishing the field in her debut by 14 3/4 lengths in the slop at Keeneland last April, the bay followed suit with another dominant win in Belmont's GI Acorn S. in June. Capturing the GI CCA Oaks at Saratoga next out July 21, she was second when last seen in the GI Cotillion...