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:
| Birth | Marriage | Became Consort | Ceased to be Consort | Death | Spouse |
| --- | --- | --- | --- | --- | --- |
| 1430/31 | 28 October 1449 | 28 October 1449 | 21 May 1481 husband's death | 10 November 1495 | Christian I |
| 25 December 1461 | 6 September 1478 | 21 May 1481 husband's ascession | 20 February 1513 husband' death | 8 December 1521 | John |
| 18 July 1501 | 12 August 1515 | 12 August 1515 | 20 January 1523 husband's desposition | 19 January 1526 | Christian II |
| 1498 | 9 October 1518 | 13 April 1523 husband's ascession | 10 April 1533 husband's death | 13 May 1568 | Frederick I |
| Interregnum (1533–1534) | Interregnum (1533–1534) | Interregnum (1533–1534) | Interregnum (1533–1534) | Interregnum (1533–1534) | Interregnum (1533–1534) |
| 9 July 1511 | 29 October 1525 | 4 July 1534 husband's ascession | 1 January 1559 husband's death | 7 October 1571 | Christian III |
| 4 September 1557 | 20 July 1572 | 20 July 1572 | 4 April 1588 husband's death | 14 October 1631 | Frederick II |
| 26 June 1575 | 27 November 1597 | 27 November 1597 | 8 April 1612 | 8 April 1612 | Christian IV |
| 24 March 1628 | 1 October 1643 | 28 February 1648 husband's ascession | 9 February 1670 husband's death | 20 February 1685 | Frederick III |
| 27 April 1650 | 25 June 1667 | 9 February 1670 husband's ascession | 25 August 1699 husband's death | 27 March 1714 | Christian V |
| 28 August 1667 | 5 December 1695 | 25 August 1699 husband's ascession | 15 March 1721 | 15 March 1721 | Frederick IV |
| 16 April 1693 | 4 April 1721 | 4 April 1721 | 12 October 1730 husband's death | 7 January 1743 | Frederick IV |
| 28 November 1700 | 7 August 1721 | 12 October 1730 husband's ascession | 6 August 1746 husband's death | 27 May 1770 | Christian VI |
| 7 December 1724 | 11 December 1743 | 6 August 1746 husband's ascession | 19 December 1751 | 19 December 1751 | Frederick V |
| 4 September 1729 | 8 July 1752 | 8 July 1752 | 13 January 1766 husband's death | 10 October 1796 | Frederick V |
| 11 July 1751 | 8 November 1766 | 8 November 1766 | 10 May 1775 | 10 May 1775 | Christian VII |
| 28 October 1767 | 31 July 1790 | 13 March 1808 husband's ascession | 3 December 1839 husband's death | 21 March/22 March 1852 | Frederick VI |
| 28 June 1796 | 22 May 1815 | 3 December 1839 husband's ascession | 20 January 1848 husband's death | 9 March 1881 | Christian VIII |
Question:
Name the became consort for marriage of 4 april 1721
Answer:
4 April 1721