Question: Who is an English singer and songwriter, who has been the leader, singer and most active songwriter of Strawbs since 1967, Terry Kath or Dave Cousins ?

Context paragraphs:
Oh How She Changed: "Oh How She Changed" is a song by English band Strawbs written by Dave Cousins and Tony Hooper.  It was the first single to be released by Strawbs and later appeared on their 1969 album "Strawbs".  An alternative mix of the song appears on the 2006 box set "A Taste of Strawbs" and a re-working on 2009's Dancing to the Devil's Beat.

Dave Cousins: Dave Cousins (born David Joseph Hindson, 7 January 1945, Hounslow, Middlesex, England) is an English singer and songwriter, who has been the leader, singer and most active songwriter of Strawbs since 1967.

Hey Little Man ... Thursday's Child: "Hey Little Man ... Thursday's Child" is a song by English band Strawbs written by Dave Cousins.  The track is to be found on the "Grave New World" album and the lyrics depict a father talking to his son.  The song can be considered to be continued on a later track from the same album – "Hey Little Man ... Wednesday's Child", which has the same tune but different lyrics.  The song is performed solely by Dave Cousins.

Blue Angel (Strawbs album): Blue Angel is a studio album by English band Strawbs.  It was the first Strawbs album in 12 years to contain new material and featured several different line-ups of musicians from past Strawbs eras.  Welsh folk-singer Mary Hopkin featured on many tracks, continuing a working partnership established by Dave Cousins and Brian Willoughby on their album "The Bridge", from which several of the tracks on this album are drawn.

Terry Kath: Terry Alan Kath (January 31, 1946 – January 23, 1978) was an American musician and songwriter, best known as the original guitarist, one of the lead singers and founding members of the rock band Chicago.  He has been praised by the band for his guitar skills and Ray Charles-influenced vocal style.

The Man Who Called Himself Jesus: "The Man Who Called Himself Jesus" is a song by English band Strawbs written by Dave Cousins.  It appears on their album "Strawbs".  An alternative mix of the song may be found on the 2006 box set "A Taste of Strawbs".

Hey Little Man ... Wednesday's Child: "Hey Little Man ... Wednesday's Child" is a song by English band Strawbs written by Dave Cousins.  The track is to be found on the "Grave New World" album and the lyrics depict a father talking to his son.  The song can be considered to be a continuation from an earlier track from the same album – "Hey Little Man ... Thursday's Child", which has the same tune but different lyrics.  The song is performed solely by Dave Cousins.

Tony Hooper: Tony Hooper (born 14 September 1943) is an English singer-songwriter and musician.  He is best known as a founder-member of Strawbs together with Dave Cousins.  He left Strawbs in 1972 after their album "Grave New World", when it became obvious that the band was moving further away from its folk roots towards rock and progressive rock.  He rejoined for a 10-year stint in 1983.  Hooper has been the guitarist in the Ceilidh & Barn-Dance Band Pitchfork since 1984, and is also a member of Misalliance.

Baroque &amp; Roll: Baroque and Roll is a studio album by Acoustic Strawbs.  Acoustic Strawbs were formed by accident after Dave Cousins and Brian Willoughby were booked to perform as a duo in Twickenham in 2000.  Cousins damaged his wrist and Dave Lambert stepped in to cover while Cousins sang.  The format was successful and tours were arranged.  Brian Willoughby stepped down in 2004 to concentrate on his work with Cathryn Craig and he was replaced by Chas Cronk who added bass pedals and acoustic bass guitar as well as extra vocals and guitar.

Hummingbird (Rick Wakeman and Dave Cousins album): Hummingbird is a studio album by Rick Wakeman and Dave Cousins.  The songs are a mixture of jointly-composed originals, reworkings of songs from Strawbs albums and Dave Cousins' solo album "Two Weeks Last Summer", together with Wakeman instrumental compositions presented as codas to the Cousins songs.

Supporting paragraphs: Dave Cousins Terry Kath
Answer: Dave Cousins