Final answer:
The angle subtended by chord AB on the major arc of the circle, given that it subtends a 140-degree angle at the center, is 70 degrees, which corresponds to the external angle on the major arc side.
Step-by-step explanation:
The angle subtended by a chord at the center of a circle is related to the angle subtended by the same chord on the circumference of the circle.
When a chord subtends an angle of 140 degrees at the center, the angle it subtends at the circumference, but specifically on the major arc, would be the external angle to the central angle.
Therefore, to find the angle subtended by chord AB on the major arc of the circle, we use the property that the angle at the center is twice the angle at the circumference.
Since the central angle is 140 degrees, the angle at the circumference on the major arc would be 360 degrees - 140 degrees = 220 degrees
However, as we are dealing with the major arc, this corresponds to the reflex angle.
To find the conventional minor angle, we subtract 220 from 360 and get 360 degrees - 220 degrees = 140 degrees.
Thus, for the angle subtended by chord AB on the most seen part (minor arc) of the circle is 140 degrees, which is option D, 70 degrees.