By Katharine Jackson WASHINGTON (Reuters) -Bipartisan U.S. Senate negotiations on how or if to respond to the latest wave of mass shootings are focused on a range of options, including improving school safety and “red flag” laws to allow police to seize guns from people deemed dangerous. The talks will continue into early this week, when Congress returns from a Memorial Day break, and follow a prime-time speech last week in which Democratic President Joe Biden implored lawmakers to act. Previous mass shootings like the ones that claimed 19 young children and two educators at a Texas school, 10…