A union member was terminated. The union filed a grievance on his behalf. Believing that the employer might have fired this employee while retaining other employees who had committed comparable offenses, the union requested that the employer provide information about the disciplinary records of its nonunion employees who had been charged with ethics or state law violations. The employer provided information about the disciplinary cases of other union-represented employees, but said that the information about nonunion employees was irrelevant. Did the employer violate the NLRA by refusing to provide the requested information to the union?