Acrolein is formed when glycerol is heated with -

$A$ triene is treated with ozone followed by zinc in acetic acid to give the following three products. What is the structure of the triene?

How many $\sigma$ and $\pi$ bonds are present in the following?
$(a)$ $But-1-ene-3-yne$
$(b)$ $Buta-1,3-diene$
$(c)$ $CH_2=CH-C\equiv N$
$(d)$ $Propa-1,2-diene$
$(e)$ $1-butyne$ and $2-butane$

What sequence of reagents is required to accomplish the following transformation?

Which of the following reagents will convert glycerol into acrolein?

The product of the reaction shown is: