Question: The 2015 Segunda División play-offs took place in June 2015 and has determined the third team which will be promoted to which season that started on 21 August 2015 and concluded on 15 May 2016?

Context paragraphs:
2015 Segunda División play-offs: The 2015 Segunda División play-offs took place in June 2015 and has determined the third team which will be promoted to the top division.  Teams placed between 3rd and 6th position (excluding reserve teams) are taking part in the promotion play-offs.

2012 Segunda División play-offs: The 2012 Segunda División play-offs took place in June 2012.  The Segunda División promotion phase (known as "Promoción de ascenso") was the second phase of 2011–12 Segunda División and was to determine the third team which promoted to 2012–13 La Liga.  Teams placed between 3rd and 6th position (excluding reserve teams) took part in the promotion play-offs.

2014 Segunda División play-offs: The 2014 Segunda División play-offs took place in June 2014 and has determined the third team which will be promoted to the top division.  Teams placed between 3rd and 6th position (excluding reserve teams) are taking part in the promotion play-offs.

2016 Tercera División play-offs: The 2016 Tercera División play-offs to Segunda División B from Tercera División (Promotion play-offs) were the final playoffs for the promotion from 2015–16 Tercera División to 2016–17 Segunda División B.  The first four teams in each group took part in the play-off.

2011 Segunda División play-offs: The 2011 Segunda División play-offs took place in June 2011.  This was "Segunda"'s first season with purely promotion play-offs since 1986–87 and the first time play offs had been used for movement between the first and second tier since 1998-99.  This new promotion phase (known as "Promoción de ascenso" ) was introduced to determine the third team which promoted to 2011–12 La Liga.  Teams placed between 3rd and 6th position, excluding reserve teams, took part in the promotion play-offs.

2015 Tercera División play-offs: The 2015 Tercera División play-offs to Segunda División B from Tercera División (Promotion play-offs) were the final playoffs for the promotion from 2014–15 Tercera División to 2015–16 Segunda División B.  The first four teams in each group took part in the play-off.

2013 Segunda División play-offs: The 2013 Segunda División play-offs took place in June 2013.  The Segunda División promotion phase (known as "Promoción de ascenso") was the second phase of 2012–13 Segunda División and was to determine the third team which promoted to 2013–14 La Liga.  Teams placed between third and sixth position (excluding reserve teams) took part in the promotion play-offs.

2015 Segunda División B play-offs: The 2015 Segunda División B play-offs (Playoffs de Ascenso or Promoción de Ascenso) are the final playoffs for promotion from 2014–15 Segunda División B to the 2015–16 Segunda División.  The four first placed teams in each of the four Segunda División B groups join the "Playoffs de Ascenso" and the four last placed teams in Segunda División will be relegated to Segunda División B.  It also decides the teams which placed 16th to be relegated to the 2015–16 Tercera División.

2017 Segunda División play-offs: The 2016–17 Segunda División play-offs took place in June 2017 and will determine the third team which will be promoted to the top division.  Teams placed between 3rd and 6th position excluding reserve teams will take part in the promotion play-offs.

2015–16 La Liga: The 2015–16 La Liga football season (known as the "Liga BBVA" for sponsorship reasons) was the 85th since its establishment.  Barcelona were the defending champions.  It started on 21 August 2015 and concluded on 15 May 2016.  Barcelona retained the title, winning it for the second consecutive season (their 24th Liga title) after beating Granada 3–0 on the final matchday.

Supporting paragraphs: 2015 Segunda División play-offs 2015–16 La Liga
Answer: 2015–16 La Liga