Please refer to the regression output below. At a 1% level of significance, how many significant variables do we have? Coefficients Std. Error tStat P-value Lower95% Upper 95% Intercept 101673.87 66200.55 1.54 0.14 -35997.71 239345.46 50.41 33.68 4.50 0.15 420.44 19.62 SH 0.40 0.13 3.19 0.00 0.14 0.66 SF\" 0.35 0.32 1.10 0.28 0.31 1.00 RES 10.28 14.60 0.70 0.49 20.07 40.64 Select one: {'31 a. All variables are significant if; b. There are no significant variables c. There is one significant variable :'_'_',: 0. There are three significant variables