Two Bars, a and B, Each of Length 2

Multiple Choice

Two bars, A and B, each of length 2.0 m and cross sectional area 1.0 m², are placed end to end as shown in the figure. The thermal conductivities of the bars are
k_A = 439 J/(s . m . K) and k_B = 887 J/(s . m . K) , respectively. The left end of bar A is maintained at 373 K while the right end of B is maintained at 273 K.
-How much heat passes the interface between A and B in 6.0 s?

A) 6.0 × 10⁴ J
B) 1.5 × 10³ J
C) 1.2 × 10⁵ J
D) 8.8 × 10⁴ J
E) 3.0 × 10⁴ J