definiens: for a given ZSS means : the period of time commencing on . the date of NN 's receipt of information relating to a Medical Hypothesis for at least one Zid Embodiment within such ZSS and ending : ( a ) upon the expiration of the Medical Hypothesis Option Period, if NN and ZGI have not agreed to proceed to PLPC for such Zid Embodiment pursuant to · ARTICLE 8 hereof ; or ( b ) if!' . 'N and ZGI have so agreed to proceed to PLPC, upon the expiration of the PLPC Option Period, ifNN and ZGI have not agreed to proceed to Clinical Proof of Concept for such Zid Embodiment pursuant to ARTICLE 8 hereof : or ( c ) if NN and ZGIhave so agreed to proceed to CPC, upon the expiration of the CPC Option Period . The is more fully described in ARTICLE 4