The midpoint of a line segment partitions the line segment into a ratio of 1: 1. 1: 2. 2: 1. 2: 3.

The answer is 1 : 1.

Step-by-step explanation:  We are given to select the correct  ratio among the given options in which the midpoint of a line segment partitions it.

As shown in the attached figure, let AB be a line segment and D be its midpoint. The, since a mid-point of a line segment divides the line into two equal parts, so we have

AD = DB.

Therefore, the ratio in which the mid-point D will divide the line segment AB is given by

Thus, the required ratio is 1 : 1.