CALCULATOR SETTINGS DAY 1, 08:30 SCOPE: 140 / 210 PROGRESS: 65% HOME THEORY MEDIA Answer the question. MISSION A positive control is a sample known to give positive results for the given test. What is the purpose of a positive control? a) Always give negative results b) Give positive results even when the procedure is not optimized c) Verify that the negative results are valid d) Valdate false-positive results