title: java IS-A relationship exam question confusion
body: <p>From MasterExam:</p>
  
  <blockquote>
    <p>Which statements are true? (Choose all
    that apply)</p>
    
    <p><code>A</code>. is-a relationship always rely on
    inheritance<br>
    <code>B</code>. is-a relationship always rely on
    instance variables<br>
    <code>C</code>. is-a relationship always require at
    least two class types<br>
    <code>D</code>. is-a relationship always rely on
    polymorphism<br>
    <code>E</code>. is-a relationship are always
    tightly coupled</p>
  </blockquote>
  
  <p>Correct answers: A, C, D</p>
  
  <p>I don't see how any of A, C or D are correct.</p>
  
  <p>An Object object IS-A Object. A String object IS-A String. There is only one class type in each of these statements and no inheritance or polymorphism applies.</p>
  
  <p>Is my rationale wrong or are the answers incorrect?</p>