Four light waves are represented by 
$\text{ (i) }\mathrm{y}={\mathrm{a}}_1\sin \mathrm{\omega t}$      $\text{ (ii) }\mathrm{y}={\mathrm{a}}_2\sin (\mathrm{\omega t}+\mathrm{\varphi })$    $\text{ (iii) }\mathrm{y}={\mathrm{a}}_1\sin 2\mathrm{\omega t}$       (iv) $\text{ (iv) }\mathrm{y}={\mathrm{a}}_2\sin 2(\mathrm{\omega t}+\mathrm{\varphi })$
Interference fringes may be observed due to superposition of 

• A

  (i) and (ii)  

• B

  (i) and (iii)

• C

  (ii) and (iv) 

• D

  (iii) and (iv)