An Experiment Was Conducted to Compare the Mean Iron Content

An experiment was conducted to compare the mean iron content in iron ore pieces determined by three different methods: (1) mechanical, (2) manual, and (3) laser. Five 1-meter long pieces of iron ore were removed from a conveyor belt, and the iron content of each piece was determined using each of the three methods. The data are shown below. How should the data be analyzed? $\begin{array}{c}\hline \text { Piece Mechanical Manual Laser } \\ \begin{array}{ l l c l} \hline 1 & 69.26 & 70.29 & 69.23 \\2 & 74.36 & 74.86 & 75.38 \\3 & 69.24 & 69.30 & 70.58 \\4 & 67.26 & 67.29 & 67.13 \\5 & 62.12 & 61.14 & 63.08 \\\hline \end{array}\end{array}$

A) randomized block design with three treatments and five blocks
B) randomized block design with five treatments and three blocks
C) completely randomized design with three treatments
D) 3 × 5 factorial design