Your project's primary constraint is quality. To make certain the project team members don't feel too pressed for time and to avoid schedule risk?

Expert judgement always work best in dealing with qualitative challenges...

I would use Reserve analysis to avoid schedule risk and to ease the time pressure from the project team members.

It's a dual act for reserve analysis through expert judgement

I dont care about the methods.

Quality and Employees both are important

A. Quantitatively based durations

To avoid schedule risk , option C - reserve analysis is used along with other tools for estimating the activity durations & thanks for the invite. 

option D is right. Expert judgement

Expert judgment is a better option.

I agree the option C Analogous estimating