Final answer:
In R, the command y <- c(1.7, "a") will make all the elements in the vector characters. This is because R coerces elements to the most complex type, in this case, characters, to maintain a consistent data type within a vector.
Step-by-step explanation:
When you create a vector using the c() function in R and include elements of different types, R will coerce all elements into the most complex type present in the vector. In the specific R code y <- c(1.7, "a"), a numeric value (1.7) and a character string ("a") are combined into a single vector. Due to R's type coercion rules, the numeric value will be converted to a character string, such that both elements in the vector are of the character data type.
The correct option to complete the sentence provided in the question is C) make. So, y <- c(1.7, "a") will make the elements all be characters. This happens because, in a mixed-type vector, R prefers the character type since it is the most flexible; it can represent any value, including numbers, as text.
Example of Type Coercion:
If we have a numeric value such as 1.7 and we combine it with a character in a vector, we can see this coercion in action:
> y <- c(1.7, "a")
> y
[1] "1.7" "a"
Here, the number 1.7 has been coerced into a string, so it now appears with quotes around it, indicating that it is a character string rather than a numeric value. This is important to understand because it affects how the elements can be used in subsequent operations; mathematical operations can no longer be performed on the "1.7" since it is now a character string.