Read the following context and choose the best option to answer the question.
Context: " I thought I 'd make sure you were feeling all right . " Sanzo 's eyes narrowed in a frown . Hakkai 's brow furrowed slightly as he continued , watching Sanzo intently .
Question: What is the reason for Sanzo 's eyes narrowing ?
Options: 
- His brow was sweaty .
 - None of the above choices .
 - Sanzo did n't believe Hakkai .
 - He was trying to focus his eyes better .


Sanzo did n't believe Hakkai .