Number of girl students=378 = $2 \times 3^{3} \times7$ = $14 \times 27$
Number of boy students=675 = $3^{2} \times5^{2}$ = $25 \times 27$
Here each can have 27 students.
Number of sections of girls = $\frac{378}{27}=14$
Number of sections of boys = $\frac{675}{27}=25$
Total number of sections = 14 +25 =39
Hence,Option(1)39.