Answer:
The statement that is correct is C. Mutations are alterations in normal DNA sequence.
Explanation:
Mutations can be described as any changes in the sequence of the DNA. These changes might occur during the time of replication due to any error or it might be caused due to chemical or environmental factors. Hence, option C best describes the mutations.
Other options are incorrect like option A is incorrect because not all mutations lead to genetic diseases. Option D is incorrect because mutations are not always inherited, they are caused due to changes in the DNA.