If the horizontal cross-sectional area of a wall is 1200 cm2, then the basic stress shall be multiplied by a reduction factor equal to________________?

If the horizontal cross-sectional area of a wall is 1200 cm2, then the basic stress shall be multiplied by a reduction factor equal to________________?

A. 0 6
B. 0.75
C. 0.85
D. 0.95