B)

Решение:

1. \( \frac{5}{12} \cdot 3 \frac{1}{3} = \frac{5}{12} \cdot \frac{10}{3} = \frac{50}{36} = \frac{25}{18} \)


2. \( 1 - \frac{7}{12} = \frac{5}{12} \)


3. \( \frac{5}{12} \cdot 2 \frac{1}{4} = \frac{5}{12} \cdot \frac{9}{4} = \frac{45}{48} = \frac{15}{16} \)


4. \( 2 \frac{1}{60} : 2 \frac{2}{5} = \frac{121}{60} : \frac{12}{5} = \frac{121}{60} \cdot \frac{5}{12} = \frac{121}{12 \cdot 12} = \frac{121}{144} \)


5. \( \frac{25}{18} + \frac{15}{16} = \frac{200 + 135}{144} = \frac{335}{144} \)


6. \( \frac{335}{144} \cdot \frac{121}{144} = \frac{40535}{20736} \)

Ответ: \( \frac{40535}{20736} \).