Which sequence describes the steps to solve a back titration?

Which sequence describes the steps to solve a back titration?

• A. Find mmols of EDTA used total; Find mmols of EDTA in excess; Take mmols total-mmols excess to find mmols of the metal used; Take mmols metal used/mL of sample to find [metal]
• B. Find mmols of EDTA in excess; Find mmols of EDTA used total; Take mmols metal used from total; Divide by mL of sample
• C. Take mmols metal used; Divide by mL of sample to get [metal]; Then determine EDTA in excess
• D. Find mmols metal in sample; Record endpoint color; Calculate [metal]

Answer: (A)