To determine which probe can be used to measure a voltage of 60V using an oscilloscope (CRO) with a maximum input of 10V, we need to understand the concept of a probe attenuation factor.

A probe attenuation factor is used to reduce the voltage seen by the oscilloscope. The most common types are:

• 1x probe: No attenuation, the CRO sees the full voltage.
• 10x probe: Voltage is attenuated by a factor of 10. If the input voltage is 60V, the CRO will only see 6V.
• 30x probe: Voltage is attenuated by a factor of 30. A 60V input would be reduced to 2V by the time it reaches the CRO.
• 1000x probe: Voltage is attenuated by a factor of 1000, reducing a 60V input to 0.06V.

Given that the maximum input voltage the CRO can handle is 10V, we need a probe that reduces 60V to less than or equal to 10V. The 10x probe attenuates the voltage by a factor of 10:

\(V_{\text{CRO}} = \frac{V_{\text{input}}}{\text{attenuation factor}} = \frac{60 \, \text{V}}{10} = 6 \, \text{V}\)

This output of 6V is within the safe input range for the CRO (10V maximum). Let's evaluate the options:

• 1x: Not suitable, as 60V would directly pass to the CRO, which exceeds its limit.
• 10x: Suitable, as it reduces 60V to 6V.
• 30x: Suitable but more attenuation than necessary, reducing to 2V.
• 1000x: Not practical for this instance as it overly attenuates the signal to 0.06V.

Therefore, the correct answer is 10x, as it reduces the voltage to a level within the CRO's limit without unnecessary attenuation.