Which counter is specifically designed to count in units of 10?

The decade counter is specifically designed to count in units of 10, making it a vital component in digital electronics, particularly in applications that need to track decimal numbers. A decade counter increments its output count from 0 to 9, and then resets back to 0 upon reaching 10, effectively cycling through ten unique states.

This behavior allows the decade counter to interface seamlessly with decimal systems, which are based on tens, and it is widely used in digital clocks, frequency counters, and other applications that require decimal counting. In contrast, binary counters convert the count to binary representation and count sequentially through powers of two but are not limited to counts of ten. Up counters and down counters refer to the direction of counting rather than any specific base. Therefore, the decade counter's focus on counting in groups of 10 clearly identifies it as the correct choice.