Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| President | Treasurer | Secretary | Social AO | Academic AO | Internal CO | External CO |
| --- | --- | --- | --- | --- | --- | --- |
| Caroline Mattias | Florian Simonsen | Menno Reijven | Christine Baljet | Arno Angerer | Jan Meijer | Elina Muceniece |
| Philipp Dienstbier | Vadim de Waart | Maria Tenberge | Catriona O'Sullivan | Svenja Engels | Isabel Voets | Simonas Savickas |
| Rogier Hanselaar | Menno van der Ven | Maria Tenberge | Roos Malmberg | Veronika Brantová | Pieter Kuijsten | Simonas Savickas |
| Rogier Hanselaar | Anne Verroen | Esmee Bergman | Roos Malmberg | Veronika Brantová | Christina Leuker | Elena Buscher |
| Harm van Leeuwen | Astrid Dalsegg | Eszter Boros | Lieke de Boer | Veronika Brantová | Christina Leuker | Elena Buscher |
Question:
What Social AO has an External CO of elena buscher, and a President of harm van leeuwen?
Answer:
Lieke de Boer