[单选题]
An object is on a frictionlejio +7 -w3rzuuss incl 7jd(t.n i/krwined plane. The plane is inclined at an angle o.tk/ nw ij(r7df $30^{\circ}$ with the horizontal. What is the object's acceleration?
A. $0.50 \; g$
B. $0.56 \; g$
C. $0.87 \; g$
D. $1.0 \; g$