题目内容：
根据以下材料，回答题Text 3
OnepertinentquestioninthewakeoftheearthquakenearAcehandthetsunamiitgeneratedishowmuchnoticeofanapproachingwavecanbegiventovulnerablepeoplewithouttheriskofcrying
"wolf"toooften.Earthquakesthemselvesareunpredictable,andlikelytoremainso.Butdetectingthemwhentheyhappenisaroutinetechnology.Thatwasnottheprobleminthiscase,which
wasobservedbymonitoring,stationsallovertheworld.Unfortunatelyfortheforecasters,althoughanypowerfulsubmarineearthquakebringstheriskofadangeroustsunami,notallsuchearthquakes
actuallyresultinabigwave,andfalsealarmscostmoneyandbreedcynicism.
Ontopofthat,most"tsunamigenic"earthquakes,whicharecausedwhentheprocessesofplatetectonicsforceheavy,oceaniccrustalrockbelowlighter,continentalrocktocreateadeeptrench
atthebottomofthesea,occurinthePacific,whichisalmostsurroundedbysuchtrenches.IntheIndianOcean,deeptrenchesareconfinedtothesoutherncoastofIndonesia,andtsunamisarerare.
Sincemostofthecountriesaffectedbythistsunamiarepoor,ormiddle-incomeatbest,
andmonitoringcostsmoney,thismightsuggestthatafatalisticapproachtothequestionisreasonable.ButAmericanandJapaneseexperiencesuggeststhateffectivemonitoringneednot
bethatexpensive.
Thesetwocountrieshavenetworksofseabedpressure--detectorsthatcanmonitortsunamisandindicatewhetherandwhereevacuationisnecessary--datatheysharewiththeirPacificneighbors.Asystemofsevendetectors,runfromHawaii,costabout$18milliontodevelop,andtheexperiencegaineddoingsomeansasimilarsystemmightnow
behadforaslittleas$2million.So,politiciansinSoutheastAsiaandAustraliaareproposingonefortheIndianOcean.
Detectingtsunamisdirectly,ratherthanrelyingonearthquakemonitors,isimportantforanotherreason,too.Notalltsunamisarecausedbyearthquakes.Someoftheworst,suchasa15-meter-highmonsterthatkilledmorethan2,000peopleinNewGuineain1998,aretheresultofsubmarinelandslides(thoughthesecanthemselvesbetriggeredbyearthquakes,aswasthecaseinNewGuinea).
Indeed,afewyearsagoitwassuggestedthatalandslideinanunstablepartofLaPalma,oneoftheCanaryIslands,mightcauseatsunamithatwoulddevastatetheeastcoastofAmerica.
Evenifyouhaveaneffectivedetectionsystem,though,itisuselessifyoucannotevacuateathreatenedarea.Here,speedisoftheessence.Computermodelingcanhelpshowwhichareasarelikely
tobesafest,butcommonsenseisoftenthebestguide--runlikewind,awayfromthesea.Evacuationwarnings,too,shouldbeeasytogiveaslongaspeopleareawake.Radiosareubiquitous,eveninmostpoorplaces.Itisjustamatterofhavingsystems
inplacetotelltheradiostationstotellpeopletorun.Theproblemwasthatnoonedid.
TheoveralldamageinAcehmighthavebeenreducedifwehad A．giventimelywarnings.
B．setupmonitoringstations.
C．detectedtheearthquake.
D．developeddetectingtechnology.
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