LYNN – Let’s have a show of hands. It’s a Sunday morning in the middle of February and you can (A) curl up on the couch in a nice, warm house with a hot cup of coffee and the newspaper, or (B) lace up your running shoes at the crack of dawn and pound the pavement for 10 or 15 miles.Option A seems to have a little more appeal, but not if you’re Mark Keaney of Lynn and the Boston Marathon is knocking on the door. Keaney will be one of the thousands of runners, from world-class athletes to the guys in Batman suits, who will tackle the 26.3-mile, 385-yard trek from Hopkinton to Boston on Monday.Why do it?”The first year I did it, I did it on a whim, or a dare,” Keaney said. “Somebody had an extra number. I was totally unprepared, but after I did it, I was hooked.”Keaney, who will be wearing No. 25825, has already run three Boston Marathons as well as one on Cape Cod. One of the things that motivates him is the challenge of just getting through the training. The other is the camaraderie. Keaney runs with the L Street Running Club in South Boston on Sundays, the day set aside for increasing (as the marathon draws closer) long runs of 10, 15,18 and beyond.”On any given Sunday, there are two or three hundred runners out there,” Keaney said. “It’s a great, great group of people. You kind of get hooked on it.”Keaney, 50, is part-owner of Bourneuf Plumbing Supply in Lynn. Two of his local running buddies, Daniel Chick of Lynn and Jared Kohane of Saugus, also work at Bourneuf. The other two are state trooper Chris Foglietta and Lynn firefighter Randy Sansone. All of them will be running the marathon.Keaney said although he recovers from the marathon fairly quickly, it does punish the body.”Being 50, every sore spot, every ache and pain, come out in the marathon. Being a weekend warrior, the Boston Marathon brings out the worst in the body,” Keaney said. “But it’s a special feeling to be able to do it, to belong to that group.”Keaney and his wife, Diane, have three adult children (Michael, Jill and Rachel) as well as a newly-minted (3-month-old) granddaughter who promises to keep him running in the near future, marathon or not.