Obtaining subsets for a fixed number of predictors

[katiehatesmath]

I am doing homework in R for my stats class and I was given these codes to put into R.

library(leaps)
subset.output = regsubsets(y~x1+x2+...+x_p, data = name of data set, nbest = 1)

so with my variables I did the first step and then I entered this code into R

subset.output=regsubsets(SuggestedRetailPrice~HorsePower+DealerCost+HighwayMPG+Weight+WheelBase,data=car.data,nbest=1)

When I put that into R, this error pops up

Error in as.data.frame.default(data) :
cannot coerce class ‘"lm"’ to a data.frame

I have no idea what I'm doing wrong and my teacher isn't helping me, can someone please help me?

[FJCC]

Is car.data a data frame? What is the result of

class(car.data)

[katiehatesmath]

I ended up figuring out what the problem was, thank you for your help!