Propose an efficient synthesis for the following transformation:

The transformation above can be performed with some reagent or

combination of the reagents listed below. Give the necessary reagents in

the correct order, as a string of letters $($without spaces or punctuation, such

as "EBF"$).$ If there is more than one correct solution, provide just one

answer.

A$.1)C{H}_{3}MgBr$; $2)H_3{O}^{+}$

B$.C{H}_{3}I$

C$.1)B{H}_3-$THF; $2)$

D$.$ PCC or DMP

E$.1)LiAl{H}_4$; $2)H_3{O}^{+}$

F$.$ conc. $H_{2}S{O}_4,$ he

G$.$ NaOEt

H$.H_{2}S{O}_4,H_{2}O,HgS{O}_4$

I. $P{h}_{3}P=C{H}_2$

J$.B{r}_2,hv$

K$.$ t$-$BuOK

L$.N{a}_{2}C{r}_2{O}_7,H_{2}S$