Final answer:
The correct DATA step statement to continue processing the last observation of a BY group in SAS is 'if last.jobtype;'. It identifies and processes the last observation in each BY group for conditional execution of statements.
Step-by-step explanation:
The question pertains to SAS programming and specifically to the use of DATA step statements in processing observations based on BY-group processing. When working with BY groups, the last.variable option is used to identify the last observation in each BY group. Therefore, the statement that indicates to continue processing the last observation of a BY group is: b. if last.jobtype;.
In a DATA step, using if last.jobtype allows you to conditionally execute statements for the last observation in each BY group. For example, if you want to perform certain calculations or output a summary only after processing all observations within a group, you would use if last.jobtype.
You can also use if last.jobtype then output; to output only the last observation of each BY group to a new dataset. However, the statement d. if last.jobtype then output=1; is incorrect as the then output=1; syntax is not valid in this context. The correct syntax would be then output; without the '=1' portion.