B. Murio
I have no explanation.
Let us first define <em>obstinado</em>. In English, this is 'obstinate', which means stubborn.
<u>The options</u>
a) <em>enfadado</em> - vexed (or even angry)
b) <em>comportamiento</em> - behavior
c) <em>tener buenos resultados</em> - to have good results
d) <em>terco</em> - stubborn
<em>Terco </em>is our synonym.
<h3>
Answer:</h3>
d) <em>terco</em>