Please help for SET (O) PBS Dependent--Urgent

Please help,

In SET (O) Application,.

In section 6 .Immigration History. there is a question, below

6.2 Since then have you had any absences from the UK? If yes, give the dates you left and
returned to the UK and the reason for the absence in the spaces below. List all absences
however short and in date order. If you need more space, continue on a separate sheet and
enclose it with your application.

My answer is Yes and I would fill the Reason of absence..

My doubt now is, There is an other question which is 6.3, below and it has some options

6.3 What evidence has been provided to support the reasons for all absences from the UK?

Do I need to select the option for this question? My closest option is below,

Letter from applicant detailing reasons for absence due to compelling or compassionate reasons. so should I select above option and do I need to write a letter though I fill Reason on absence on 6.2..

Please help