Four pairs of numbers have been given, out of which three are alike in some manner, while one is different. Choose out the odd one.

 we have given the option we check different 

(A) 16 - 64    

$$16 \times \dfrac {16}{4}$$  

$$\Rightarrow 16 \times 4$$ = 64

then 16 - 64

we check option (B) 26 - 168 

$$26 \times \dfrac {26}{4} $$

$$\Rightarrow 26 \times 6.5 $$ = 169 

then 26 - 169 Right but given 26-168 

we check (C) 34-289 

$$ 34 \times \dfrac{34}{4} $$

$$\Rightarrow 34 \times 8.5 $$ = 289

Again we check option (D) 18-81

$$18 \times \dfrac{18}{4} $$

$$\Rightarrow 18 \times 4.5 $$

$$\Rightarrow 81 $$

then 18-81 

therefore we can say A, C,D follow same pattern but B is not followed

therefore  option (B) is different another option 

Ans (C) 26-168