Antonio has found that he can input statistical data into his computer at the rate of 2 data items faster each half hour he works. One Monday, he starts work at 9:00A. M., inputting data at a rate of 3 data items per minute. At what rate will Antonio be inputting data into the computer by lunchtime (noon)?
A. 12 data items per minute
B. 15 data items per minute
C. 21 data items per minute
D. 24 data items per minute