Which drawing is a structural model of C3Hg?

The correct option is C

Explanation:

The structural model of C₃H₈ is that of option C.

In Structural model which can also be known as structural formula, the atoms of a molecule or compound are identified by the location of chemical bonds that exists between them. A structural formula is seen to consist of symbols. In this case, the atoms are connected by short lines. These short lines actually represent their chemical bonds. Where one, two, or three lines that  connect each element that make up the compound stands for single, double, or triple bonds, respectively.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.