K= (D0+A'+B').(D1'+D0+A+B).(D1+D0'+A).(D1'+D0'+A'+B).(D0'+A+B')


truth table (not(D1) or D0 or A or B) and (D1 or not(D0) or A) and (not(D1) or not(D0) or not(A) or B) and (not(D0) or A or not(B) ) and (D0 or not(A) or not(B))
	  
	  
	  
	  
	  
	  (not(D1) or D0 or A or B)						(D1 or not(D0) or A)
	  
truth table not( not(  (not(D1 and not(D0) and A and not(B))) and (not(not(D1) and D0 and not(A)))   ))


(not(D1) or not(D0) or not(A) or B) -------> (not((D1 and D0 and A and not(B)))) 


(not(D0) or A or not(B) ) -----> (not(D0 and not(A) and B))


(D0 or not(A) or not(B))  ----------> (not(not(D0) and A and B ))



Final equation using only NAND

truth table not( not(  (not(D1 and not(D0) and A and not(B))) and (not(not(D1) and D0 and not(A))) and (not((D1 and D0 and A and not(B)))) and (not(D0 and not(A) and B)) and (not(not(D0) and A and B ))   ))

too long ..... 

Let's use Proteus instead WolframAlpha for this demonstration