With no explanation, chose the best option from "A", "B", "C" or "D". of identity, authority and purpose, unless exigent circumstances require his immediate forcible entry. (c) If the officer is not .admitted after such reasonable period, he may forcibly enter the premises and may use as much physical force to effect entry therein as is necessary to execute the Search. See also Commonwealth v. McDonnell, 512 Pa. 172, 516 A.2d 329 (1986). Here, the warrant authorized a search of the defendant’s second floor apartment at 925 South Queen Street. Given this description, we believe that it was reasonable for the police to open the unlocked front door without knocking and enter the vestibule area. This area contained mailboxes, stairs and the door to what appeared to be a first floor apartment. See United States v. Acosta, 965 F.2d 1248 (3rd Cir. 1992) (<HOLDING>). Detective Roberts thereafter yelled up

A: holding that the defendant had no expectation of privacy in the hallway of an apartment building where the building door was unlocked and the hallway was easily accessible to the public
B: holding that defendants lacked a reasonable expectation of privacy in common area of residential building
C: holding that a dog sniff outside the defendants door in his apartment building was not a search within the meaning of the fourth amendment so long as the police were lawfully present in the hallway when the search occurred
D: holding that the defendant had a duty to retreat from the doorway between his apartment and the apartment hallway because that area functioned as a hybrid privatepublic space
A.