The clock will be ticking when Reba McEntire sings the national anthem at Super Bowl 58 in Las Vegas on Sunday (Feb. 11). One of the most popular prop bets is on the length of the national anthem before the Super Bowl. The current over/under on the length is set at 90.5 seconds. Before we get to where the smart bet may be, let’s take a look at how some other singers have done with the task. The first country guest performer at a Super Bowl was Charley Pride, in 1974 at Super Bowl VIII in Houston, Texas. Since then, a wide range of artists across all genres have taken on the task. Neil Diamond,…