|Question 17Verbal

Source Texts

Text
In the periodic table, an element's atomic number indicates how many protons there are in an atom of the element. For example, a helium atom        2 protons. Professor Raymond Chang explains this concept in more detail in the textbook Chemistry.
Which choice completes the text so that it conforms to the conventions of Standard English?
have
A
has
B
is having
C
had
D