Verify each option
Multiply the probability by the repair cost
so
A1 ----->0.25*10=2.5
B2-----> 0.23*8=1.84
C3 -----> 0.4*9=3.6
A4 ----> 0.35*8.5=2.975
therefore
the best refrigerator is B2
because the probability of failing is the less value and its repair cost is the less value too