From the options given below, select the correct meaning and explanation of the expression:

"At face value"

What one appears to be

The correct meaning of the expression "at face value" is option 1: what one appears to be. It means to accept something as it is presented, without questioning or investigating further. For example, if someone tells you that they are a millionaire, you might take their word for it at face value. However, you might also want to do some research to see if their claim is true.

The other options are incorrect. Option 2, the value of ornaments worn on the face, is the literal meaning of the phrase "face value". However, it is not the idiomatic meaning of the phrase. Option 3, the additional value of the gems worn on the face, is not a common expression. Option 4, the value of one's smile, is also not a common expression and does not have the same meaning as "at face value".