Nymex crude oil wavers as Brent falls further

    By V. Phani Kumar     U.S. crude-oil prices fluctuated between gains and losses in electronic trading Tuesday, even as Brent futures extended their loss to narrow the difference between the rival benchmarks amid a possible easing of geopolitical tensions.     West Texas Intermediate crude-oil futures for delivery in May CLK2 +0.08% were down 2...