This is a great question! One we have not answered recently here at AAP.

We’ll start with this.  At FAR 36.601-3(b) ”Sources for contracts for architect-engineer services shall be selected in accordance with the procedures in this subpart rather than the solicitation or source selection procedures prescribed in parts  13, 14, and 15 of this regulation.”  (bold and italics) added for emphasis.  Selection of Architects and Engineers (formerly known as the Brooks Act of 1972) are used and FAR subpart 36.6 does not preclude the use of options.

Also, notice at FAR 17.202 Use of options and FAR 17.202(a) it mentions “for both sealed bidding and contracting by negotiation”.  It does not include the Selection of Architects and Engineers found at FAR subpart 36.6.  I forget the Latin term but in regulatory interpretation there is a concept called “the inclusion of some is the exclusion of others” or something like that.

So, you do not need to document use of options IAW FAR 17.205(a).  Where you will justify the use of options is when you do Acquisition Planning.  FAR 7.102(a) mentions “all acquisitions”.

See FAR 7.105(b)(5), this is where the requirement is to discuss/consider rationale for the use of options.

Additional Reference (caveat I’m not sure if this is still an active document), but USACE EP 715-1-7 dated 29 February 2012 Architect-Engineer Contracting in USACE discusses this as well.