Answer:
d. both a and b above, but not c
Explanation:
<u>Apostrophes can be used to form possessive case</u> it order to indicate possession; for example:
<em>the neighbours' house</em>
<em>the children's bedroom</em>
<em>the man's car</em>
Besides,<u> apostrophes mark contractions</u>, such as the verb <em>to be</em> and auxiliary verbs like<em> has, have, had </em>and <em>would, </em>in affirmative and negative forms:
<em>Mary's a good student.</em>
<em>I've been to London twice.</em>
<em>She hasn't finished her homework yet.</em>
<em>When I got home, they'd already had dinner.</em>
<em>I'd like a cup of coffee, please.</em>
On the other hand, <u>regular plural forms do not take apostrophe but the suffix </u><u><em>-s</em></u>.
<em>book - books</em>
<em>dog - dogs</em>
<em>memory - memories</em>
