When 1000 units are 60% complete in a process, it is equivalent to . . . . . . . . completed units.

The correct answer is $\boxed{\text{B) 600}}$.

To solve this, we can use the following formula:

• Completed units = (Total units)(Percent complete)

In this case, we have:

• Total units = 1000
• Percent complete = 60%

Therefore, the number of completed units is:

• Completed units = (1000)(60%) = 600

Option A is incorrect because 60 is not equal to 600.

Option C is incorrect because 6000 is not equal to 600.

Option D is incorrect because 1000 is the total number of units, not the number of completed units.