I believe the answer you are looking for is Generous and serving
I would think it to be B. A, C, and D all have something to do with words whereas B is math which isn't quite the same.
To give you an idea, a gerund<span> phrase will begin with a </span>gerund<span>, an ing word, and will include other modifiers and/or objects. </span>Gerund<span> phrases always </span>function<span> as nouns, so they will be </span>subjects<span>, </span>subject<span> complements, or objects in the </span><span>sentence</span>
<span>A predicate nominative is a subject complement, a word or group of words that follows a linking verb or verb phrase such as is, are, was, has been, and can be. It renames, identifies, or defines the subject or subjects.</span>