Correct Answer: Monitour

Solution : The correct choice is the first option.

The word "monitour" is misspelt. The correct spelling is monitor, which refers to a device or person that observes, checks, or keeps track of something.

Other words are correctly spelled, and their meanings are as follows:

• Slope: It is an incline or a surface that slants or tilts, typically rising or falling.
• Constant: This refers to something that is unchanging, consistent, or continual. It does not vary or fluctuate.
• Chemical: This pertains to chemistry or chemicals, which are substances with a distinct molecular composition produced by or used in a chemical process.

Therefore, the incorrectly spelled word is monitour.