The following was enciphered with a Vigenere cipher. Find the key and decipher it$.$ Code to compute Index of Coincidence $($IC$).$

UPRCW IHSGY OXQJR IMXTW AXVEB DREGJ AFNIS EECAG SSBZR TVEZU RJCXT OGPCY OOACS EDBGF ZIFUB KVMZU FXCAD CAXGS FVNKM SGOCG FIOWN KSXTS ZNVIZ HUVME DSEZU LFMBL PIXWR MSPUS FJCCA IRMSR FINCZ CXSNI BXAHE LGXZC BESFG HLFIV ESYWO RPGBD SXUAR JUSAR GYWRS GSRZP MDNIH WAPRK HIDHU ZBKEQ NETEX ZGFUI FVRI

You may work on part of it by hand $($like which IC to choose$).$

You may reuse work from question $1$ here once you have found the period and split the alphabets accordingly.

Must show your work in detail. $[20]$