virtual agents Select one: O a. phishing and trust. Deceive people into parting with personal details O b. welcoming persona, has a personality and makes the user feel involved with them O c. tries to persuade people to change their everyday habits with respect to environmental concerns The gulf of execution refers to Select one: O a. The user's difficulty in understanding the feedback from the system b. The system's difficulty in presenting information in the output language c. The system's difficulty in converting an input expression into the correct system state transition Od. The user's difficulty in formulating and articulating an intention to the system