<p>Makes no difference. Take the three you think you'll do best on.</p>
<p>I myself took three: Math II, Biology and English.</p>
<p>Just make sure you follow the instructions that the colleges you are applying to give. Some may require that you take one of the math exams, or the English one.</p>
<p>Here are links to the Harvard Admissions Office on their SAT II policy. Good luck.</p>
<p>-Greg</p>