A girl purchased “m” number of pens of type “A” at the unit price of “Rs. x” each, “n” number of pens of type “B” at the unit price of “Rs. y” each and “p” number of pens of type “C” at the unit price of “Rs. z” each. Which of the following represents the average price of all the pens taken together?

• A. (mx + ny + pz) / (m + n + p)
• B. (mA + nB + pC) / (m + n + p)
• C. (mA + nB + pC) / (A + B + C)
• D. (mx + ny + pz) / (A +B + C)