Question: Who served as both the Prime minister and Foreign minister in the 1980's to the sovereign country consisting of six major islands and over 900 smaller islands in Oceania?

<P0-S0>  The country's capital, Honiara, is located on the island of Guadalcanal. <P0-S1> Solomon Islands is a sovereign country consisting of six major islands and over 900 smaller islands in Oceania lying to the east of Papua New Guinea and northwest of Vanuatu and covering a land area of 28400 km2 . <P0-S2>  The country takes its name from the Solomon Islands archipelago, which is a collection of Melanesian islands that also includes the North Solomon Islands (part of Papua New Guinea), but excludes outlying islands, such as Rennell and Bellona, and the Santa Cruz Islands. <SEP> <P1-S0> Australia ( , , ), officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania and numerous smaller islands. <P1-S1>  It is the largest country in Oceania and the world's sixth-largest country by total area. <P1-S2>  The neighbouring countries are Papua New Guinea, Indonesia and East Timor to the north; the Solomon Islands and Vanuatu to the north-east; and New Zealand to the south-east. <P1-S3>  Australia's capital is Canberra, and its largest urban area is Sydney. <SEP> <P2-S0> Ezekiel Alebua PC (born 1947) was the third Prime Minister of the Solomon Islands from 1 December 1986 until 28 March 1989. <P2-S1>  He served as Foreign Minister from 1981 to 1982. <P2-S2>  Alebua was the premier of Guadalcanal province from 1998 to 2003, and antagonised some people in that area for not supporting moves to declare that province independent. <SEP> <P3-S0> The Swedish constitution of 1974 allows the Prime Minister of Sweden to appoint one of the Ministers in the cabinet as Deputy Prime Minister ("biträdande statsminister", also unofficially known as "vice statsminister", "Vice Prime Minister"), in case the Prime Minister for some reason is prevented from performing his or her duties. <P3-S1>  However, if a Deputy Prime Minister has not been appointed, the Minister in the cabinet who has served the longest time (and if there are several with equal experience the one who is oldest) takes over as head of government. <P3-S2>  Note that the person acting as Prime Minister does not do so on a permanent basis: if a Prime Minister dies, resigns or loses a vote of confidence in the Riksdag, the Speaker of the Riksdag will then confer with the parties of the Riksdag and propose a new Prime Minister, who must be tolerated by a majority of the Riksdag. <P3-S3>  If the Prime Minister has resigned or lost a vote of confidence, he or she will remain the head of a government "ad interim" until the new Prime Minister assumes his or her office. <P3-S4>  The only case where the governmental line of succession becomes relevant is when the Prime Minister dies (upon which the person next in the line of succession serves as the head of a government "ad interim") or when the Prime Minister is on leave or for any other reason incapable of serving, but still remains in office. <P3-S5>  This might be compared to the Presidential line of succession in the United States, where the person next in line assumes the Presidency throughout the remainder of the term if the President dies, resigns or is impeached.