Figure plots the continuous-phase arg[H(e^j?)] for the frequency response of a specific LTI system, where?

arg[H(e^j?)] = ???

for |?|

?Is the impulse response h[n] of this system a causal sequence? If the system is definitely causal, or if it is definitely not causal, give a proof. If the causality of the system cannot be determined from Figure, give examples of a noncausal sequence and a causal sequence that both have the foregoing phase response arg[H(e^j?)].

argjH(e |