Answer
a. Secondary voltages, greatest to least: B, C, A.
b. Secondary current, greatest to least: A, C, B.
c. Secondary power output, greatest to least: A=B=C.
Work Step by Step
a. Use the transformer rule.
$$\frac{primary \; voltage}{\# \; of \; primary \; turns} = \frac{secondary \; voltage}{\# \; of \; secondary \; turns}$$
$$\frac{(primary \; voltage)(\# \; of \; secondary \; turns)}{100 \; turns} = (secondary \; voltage)$$
The greater the number of turns on the secondary, the more the voltage is stepped up.
Secondary voltages, greatest to least: B, C, A.
b, c. The power in the secondary is the same as that in the primary, by conservation of energy. The product of voltage and current stays the same, so the larger the secondary voltage, the smaller the secondary current.
Secondary current, greatest to least: A, C, B.
