Answer:
B. Ordinal
Explanation:
First we need to identify if the data is qualitative or quantitative. The measurement scale of Qualitative data can be either Nominal or Ordinal while for Quantitative data it would be either Interval or Ratio Level.
In the given case the data is name of the subjects: Science, Mathematics and Management which clearly is Qualitative Data. Now we need to see if the data is at Nominal Level or Ordinal Level.
Data at Ordinal level can be put into some order while data at Nominal Level cannot be put into order. Since the professor is able to rank the subjects based on preferences of students, he is establishing a relation between subjects by putting them in an Order.
Hence, the measurement scale the professor employed was Ordinal.