Which of the following is a valid option in PROC PRINT for limiting output?

The option that is valid in PROC PRINT for limiting output is FIRSTOBS=. This option allows you to specify the starting observation number from which to begin printing. For example, if you set FIRSTOBS=5, PROC PRINT will only display the data starting from the fifth observation onward. This is particularly useful when working with large datasets, as it enables you to focus on a specific subset of the data.

Using FIRSTOBS= in PROC PRINT helps in viewing particular sections of the dataset without overwhelming output. In combination with the OBS= option, you can further manage the range of observations that are printed, allowing for better data management during analysis.

In contrast, LIMIT= is not a recognized option in PROC PRINT and does not serve a function in this context. SHOW= does not exist in PROC PRINT either, and while RETAIN= is an option frequently used in data step programming to control variable retention across iterations, it does not apply to PROC PRINT. Thus, FIRSTOBS= is the only option here that directly relates to limiting the output of PROC PRINT.