Explanation:

Formation of a magnified real image by a convex lens depends on the position of the object with respect to the lens. Let us understand the four options given in the question and which one is correct.

a) F: When an object is placed at the focal point of a convex lens, a real image is not formed. This is because the rays of light coming from the object are parallel to each other after passing through the lens and hence, do not converge to form an image. Therefore, this option is incorrect.

b) Infinity: When an object is placed at infinity from a convex lens, the rays of light coming from the object are parallel to each other. These parallel rays converge at the focal point of the lens and form a real, inverted and highly diminished image. Therefore, this option is also incorrect.

c) 2F: When an object is placed at 2F, the rays of light coming from the object converge at a point which is at a distance of 2F from the lens on the other side. This point acts as a virtual focus for the lens. The image formed is real, inverted and of the same size as the object. Therefore, this option is also incorrect.

d) Between F and 2F: When an object is placed between F and 2F, the rays of light coming from the object converge at a point which is beyond 2F on the other side of the lens. The image formed is real, inverted and magnified. The size of the image depends on the position of the object. When the object is placed closer to F, the image formed is larger and as the object moves closer to 2F, the image formed becomes smaller. Therefore, this option is correct.

Conclusion:

Hence, we can conclude that a magnified real image is formed by a convex lens when the object is placed between F and 2F.