I believe the answer is D.
        
                    
             
        
        
        
False, It will basically be a carbon sink. Taking in more than it produces.
        
                    
             
        
        
        
9:3: 3:1  is the phenotypic ratio showing traits as black and long hair : black and short hair: chestnut and long hair: chestnut and short hair when a chestnut horse heterozygous for pacing and hair length with a hybrid horse. 
Explanation:
Dominant trait = black hair colour (BB,Bb), trotting (TT,Tt) , long hair (LL,Ll)
recessive trait = chesnut hair colour (bb), pacing gait (tt), short hair(ll)
cross between chestnut horse heterozygous for pacing and hair length will have alleles as BbLl 
alleles for hybrid horse will also be heterozygous Bb, Ll
Punnett square to show the cross:
       BL         Bl       bL         bl
BL  BBLL  BBLl     BbLL    BbLl
Bl   BBLl    BBll     BbLl      Bbll
bL  BbLL  BbLl      bbLL     bbLl
bl    BbLl  Bbll       bblL        bbll
phenotype ratio 
black and long hair : black and short hair: chestnut and long hair: chestnut and short hair
9:3: 3:1  is the phenotype ratio.