Final answer:
To assign values to specific elements of a vector, you can use the indexing notation. Option B 'myvector[1] = 99' is the correct statement for assigning the value 99 to the second element of the vector.
Step-by-step explanation:
To assign values to specific elements of a vector, you can use the indexing notation. For example, if you have a vector called 'myvector', you can assign the value 99 to the first element by using the notation 'myvector[0] = 99'. Similarly, you can assign values to other elements using the same notation. So, based on the given options, option B 'myvector[1] = 99' is the correct statement for assigning the value 99 to the second element of the vector.