Instruction: Given the products the user has purchased in history, rank the items in the listed options and output the item that the user is most likely to purchase next. Answer from one of the options.

Input:
1st: Canon PowerShot SX510 HS 12.1 MP CMOS Digital Camera (discontinued by manufacturer). Electronics. Camera & Photo. Canon.
2nd: ELEC 4Ch Channel HDMI 960H H.264 CCTV DVR with 500GB Hard Drive and 4 Bullet 700TVL Outdoor Cameras Realtime CCTV Network Security Home Surveillance System...
3rd: Nexus 7 Case, JETech Slim-Fit Case Cover for Google Nexus 7 2013 Tablet w/Stand and Auto Sleep/Wake Function (Black). Electronics. Computers & Accessories. JETech.
4th: BM Premium 2-Pack of LP-E10 Batteries for Canon EOS Rebel T3, T5, T6, T7, Kiss X50, Kiss X70, EOS 1100D, EOS 1200D, EOS 1300D, EOS...
5th: Lens Cap Bundle - 4 Snap-on Lens Covers for DSLR Cameras including Nikon, Canon, Sony - Lens Cap Keepers included (58mm). Electronics. Camera & Photo...
6th: iPad Air Case, SUPCASE Heavy Duty Beetle Defense Series Full-body Rugged Hybrid Protective Case Cover with Built-in Screen Protector for Apple iPad Air (Black/Black, not...
7th: 58mm Multi-Coated UV Protective Filter For Canon Digital EOS Rebel SL1, T1i, T2i, T3, T3i, T4i, T5, T5i EOS60D, EOS70D, 50D, 40D, 30D, EOS 5D,...

Options:
A: Bosch PB120 12-Volt Max Lithium-Ion Compact AM/FM Radio with MP3 Player Connection Bay. Electronics. Portable Audio & Video. Bosch.
B: Outdoor Cap Team Logo Cap with Camo Trim, One Size, Realtree Blaze/APX. Sports & Outdoors. Sports & Fitness. Outdoor Cap.
C: B BELK-MacBook Pro 13" with Retina Display Case,2 in 1 Plum Blossom Series Glitter Bling PC Hard Case with Keyboard Cover for MacBook Pro 13"...
D: Creative Hobbies Box of 25 Colored Light Bulbs, Random Blinking, 7 Watt, C7 Candelabra Base -Great for Night Lights and Christmas Strings. Home & Kitchen...
E: Grip Strength Trainer and Hand Strengthener - Hand Grip Strengthener and Grip Rings with 10-100lb Resistance - This Forearm Grip Workout is The Best Hand...
F: LG Electronics Q Series 24M45VQ 24-Inch Screen LED-Lit Monitor. Electronics. Computers & Accessories. LG.
G: Greenland Katy Dec. Pillow Pair Accessory-Multi, Multicolor. Home & Kitchen. Bedding. Greenland.
H: M.V. Trading Deluxe Portable Butane Stove Free Carry Case. Sports & Outdoors. Outdoor Recreation. M.V. Trading.
I: SquareTrade 2-Year Housewares Extended Protection Plan ($200-249.99). Electronics. Electronics Warranties. SquareTrade.
J: Hollowick Disposable Liquid Paraffin, 12-Pack. Home & Kitchen. Home Dcor. Hollowick.
K: LIIDA Curtain Lights, LED Twinkle Lights 9.8 x 9.8ft Warm White Curtain Icicle Lights With 8 Modes Controller for Holiday, Party, Outdoor Wall, Wedding Decorations...
L: Norpro Expanding Over the Sink Colander with Base Frame. Home & Kitchen. Kitchen & Dining. Norpro.
M: Caldwell Optic Armor Scope Cover. Sports & Outdoors. Sports & Fitness. Caldwell.
N: WD  My Passport Elite 250 GB USB 2.0 Portable External Hard Drive (Titanium). Electronics. Computers & Accessories. Western Digital.
O: Onyx A-24 In-Sight Automatic Inflatable Life Jacket, Red. Sports & Outdoors. Sports & Fitness. Absolute Outdoor.
P: Flash Furniture Contemporary Top Hat Chocolate Microfiber Rocker Recliner. Home & Kitchen. Furniture. Flash Furniture.
Q: GI Medical Instrument and Supply Set Case - OD. Sports & Outdoors. Outdoor Recreation. Military.
R: Geilienergy Rechargeable Battery Compatible with AT&T and Vtech Phones BT-8300 / BATT-6010 / BT18433 / BT184342 / BT28433 / BT284342 / 89-1326-00-00/89-1330-01-00 / CPH-515D/bt-1011 (Pack...
S: Green Blob Outdoors Superior Tactical (Dark Earth / Tan) Flip up Front and Rear Iron Sights Set.  Green Blob Outdoors.
T: Super Power Supply® USB Plug Charger Cord for Samsung Galaxy Tablet Charge (Charging) & Data Sync Cable USB to 30 Pin Adapter Tab 7" 8.9"...
Answer: R