Classify the following variables into the correct level of data (nominal, ordinal, interval, or ratio):

a. Number of Facebook friends

b. Height, measured in centimeters

c. Reaction time

d. Kelvin temperature scale

e. Race/ethnicity

f. Native language

g. Military rank

h. Celsius temperature scale

i. College major

j. Movie content ratings (e.g., G, PG, PG-13, R, NC-17)

k. Personality type

l. Hours spent watching TV per week

m. Percentage of games an athlete plays without receiving a penalty

n. Marital status (i.e., single, married, divorced, widowed)

o. Fahrenheit temperature scale.