Data were collected in twenty major urban areas on the percent of women in the labor force. Data were collected in 1968 and again in 1972. Gains or losses in this percent were the basis for discussing whether or not there had been an increase in percent of women in the labor force over the period. What kind of design was this? 1. A matched-pairs design Il. A randomized block design Ill. An observational study O A. I only B. II only O C. Ill only O D. I and ll only O E. I and Ill only