Concept:Commission is a percentage of the total sales: commission = rate × sales.Given:Commission rate = 15%, commission earned = GHC 60.00.Solution:Let total sales be S.15% of S=6010015×S=60S=1560×100=156000=400Check: 15% of 400=0.15×400=60 ✓.So she made sales of GHC 400.00.Answer:Option C (GHC 400.00)