The question only permit us to drop bands not replace them with clips

If you drop 5 bands
you have 3 bands and 2 clips

3*60+2*40=260

260/5=52

THE Answer is E

Average = Sum / N--------- (I)
given: Average= 56 for N=10
Sum = Average * N
= 56*10= 560------- (a)

Required Average= 52

Use Strategy: Check Answer Choices-(BD Strategy)

after checking: E = 5 from answer choice (means put back 5 bands and price of each band is 60. therefore price of 5 bands= 5*60= 300---- (b)
after putting back 5 bands, we are left with items----- 10-5= 5 ------ (u)
Sum of amount left= a-b = 560-300= 260----- (v)

now using equation (I),
Average = 260/5 = 52 ( 260 and 5 from 'v' and 'u' respectively)
correct choice: E