The correct combination of the following groups of sentences "The boy climbed up to the top of the tower. The tower was steep and tall. The boy was my younger brother. There was none other" would be --
The boy having climbed up to the top, steep tower was my younger brother
The boy who climbed up to the top, steep tower was my younger brother
The boy who climbed up to the tall tower all alone was my younger brother
The boy climbing the top, steep tower was my younger brother