Interconversion of terminal to internal alkyne and vice versa takes place by the following reagents (A) and (B).

Reagents (A) and (B) are:

• A

  ${\mathrm{NaNH}}_2\text{ and }{\mathrm{NaNH}}_2$

• B

  $\text{ alc. }\mathrm{KOH}\text{ and }{\mathrm{NaNH}}_2$

• C

  $\text{ alc. }\mathrm{KOH}\text{ and }\mathrm{P}-2\text{ catalyst }$

• D

  ${\mathrm{NaNH}}_2\text{ and Lindlar's catalyst }$