Explanation:

A degree-of-freedom planar mechanism is a mechanism that is constrained to move in a single plane and has only one degree of freedom, which means that it has only one independent motion.

Higher and lower kinematic pairs are two types of joints that are used to connect the links of a mechanism.

- Higher kinematic pairs have point or line contact between the two links, such as a revolute or a prismatic joint.
- Lower kinematic pairs have surface or area contact between the two links, such as a planar or a spherical joint.

To determine the minimum number of links in a single degree-of-freedom planar mechanism with both higher and lower kinematic pairs, we need to consider the following:

- A single degree-of-freedom mechanism has only one independent motion, which means that it can have only one input and one output.
- The input and output can be connected by a higher kinematic pair to form a four-bar linkage, which is the simplest type of mechanism with both higher and lower kinematic pairs.
- A four-bar linkage has four links and four joints, which can be connected in different ways to form different types of mechanisms.

Based on the above considerations, we can conclude that the minimum number of links in a single degree-of-freedom planar mechanism with both higher and lower kinematic pairs is four. This can be achieved by connecting the input and output links by a higher kinematic pair and connecting two intermediate links by lower kinematic pairs to form a four-bar linkage.

Therefore, the correct answer is option C, which states that the minimum number of links in such a mechanism is 4.

Here h is not equals to zero, so i think ans is d