Bernard and Adriana grew sunflowers in their backyard. Bernard's sunflower grew 4.23 cm in one week and 8.91 cm the second week. Adriana's sunflower grew 15.12 cm in two weeks. Round each number to the nearest tenth. About how much more did Adriana's sunflower grow than Bernard's? A. about 1.7 cm B. about 1.8 cm C. about 1.9 cm D. about 2.0 cm