Which option sets the upper limit for observations read in a SAS data set?

The option that sets the upper limit for observations read in a SAS data set is "obs=". This option allows users to specify the maximum number of observations that SAS will process from the data set. By using "obs=", you can control how many records SAS reads and processes during a data step or procedure, which can be particularly useful for managing large data sets or for testing purposes when you want to work with a smaller sample of the data.

For instance, if you specify "obs=100", SAS will only read the first 100 observations from the data set, allowing you to speed up computations or analysis. This is an essential feature for users who need to optimize performance or focus on specific segments of their data.

The other options do not control the number of observations read. The option "firstobs=" is used to indicate the starting point of the observations to be read, but it does not limit the total number of observations. "linesize=" and "pagesize=" are related to the formatting of output rather than controlling the number of observations read from a dataset.