The correct answer is $\boxed{\text{B) 0.97}}$.
Accuracy is the percentage of instances that are correctly classified. It is calculated by dividing the number of correct classifications by the total number of classifications. In this case, there are 14 + 15 + 6 = 35 total classifications, and 14 + 15 = 29 of them are correct. Therefore, the accuracy is $\frac{29}{35} = 0.97$.
Option A is incorrect because it is the accuracy of a two-class classification. Option C is incorrect because it is the accuracy of a four-class classification. Option D is incorrect because it is the accuracy of a five-class classification.