Lean operations is aimed at "reducing waste." There are two key types of waste $($each with two sub$-$types$)$:

$1)$ Excess process time $($the time it takes to perform the process steps$).$ This can come in $2$ forms:

a$)$ Doing something that does not add value.

b$)$ Taking too long to do something that does add value.

$2)$ Excess variability in the process flow. This can come in $2$ forms:

a$)$ Variation in the way the process is performed $($not doing it "the best way" every time$).$ This reduces quality and leads to variation in process time.

b$)$ Variation in job interarrival times relative to job completion times $($e$.$g$.,$ patients not arriving at the proper regular intervals$).$

Let's say a hospital works to get patients to adhere to specific appointment times. This would be an example of reducing waste of type:

Group of answer choices

$1-$a

$2-$b

$2-$a

$1-$b