The correct order of alkene reactivity towards an electrophile is mentioned in:

In which reaction the product following Anti-Markovnikov's rule is observed?

Product P is 

${\mathrm{CH}}_3\mathrm{CH} = {\mathrm{CH}}_2 \underset{{\mathrm{H}}_2{\mathrm{O}}_2/{\mathrm{OH}}^{-}}{\overset{{\mathrm{BD}}_3/\mathrm{THF}}{\to }}\mathrm{X}$

Identify product $\mathrm{X}$ is:

cis$-2-$Butene $\stackrel{\mathrm{HOBr}}{\to }\mathrm{P}$

Identify product $\text{'}\mathrm{P}\text{'}$ is:

The major product of the following reaction is: