SENTENCE is in the present PERFECT TENSE. The present perfect tense is used to express those actions which have finished recently.Structure - Subject + has/have + V3 + Object.Thus, the phrase in the blank also has to FOLLOW the same PATTERN. Hence, option 2 'had passed' and option 3 'had been passing' cannot be the answers because they exhibit past perfect and past perfect continuous tense respectively.The verb 'saw' means that the act is complete. Thus, the verb 'been' cannot be used in the continuous tense. Therefore, option 1 is the correct answer.Complete sentence: Years have passed since I saw her last.TenseSimple tenseContinuous tensePerfect tensePerfect continuousPresent v1+s/esis/am/are+v1+inghas/have+v3has/have been+v1+ingPastv2was/were+v1+inghad+v3had been+v1+ingFuturewill/shall+v1will be+v1+ingwill have+v3will+have been+v1+ing वाक्य Present perfect tense में है।Presnt perfect tense का उपयोग उन क्रियाओं को व्यक्त करने के लिए किया जाता है जो हाल ही में समाप्त हुई हैं।संरचना - Subject + has/have + V3 + Object.इस प्रकार, रिक्त स्थान के वाक्यांश को भी उसी पैटर्न का पालन करना है।इसलिए, विकल्प 2 'had passed' और विकल्प 3 'had been passing' उत्तर नहीं हो सकते क्योंकि वे क्रमशः past perfect और past perfect continuous tense को प्रदर्शित करते हैं।क्रिया 'saw' का अर्थ है कि कार्य पूरा हो गया है।इस प्रकार, क्रिया 'been' का प्रयोग सतत काल में नहीं किया जा सकता है।TenseSimple tenseContinuous tensePerfect tensePerfect continuousPresent v1+s/esis/am/are+v1+inghas/have+v3has/have been+v1+ingPastv2was/were+v1+inghad+v3had been+v1+ingFuturewill/shall+v1will be+v1+ingwill have+v3will+have been+v1+ing अतः सही वाक्य है - Years have passed since I saw her last.