Which one of the following longitudes determines the Indian standard time? [2009-I]

• A.  \[85.5{}^\circ \text{ }E\]
• B.  \[86.5{}^\circ \text{ }E\]
• C.  \[84.5{}^\circ \text{ }E\]
• D.  \[82.5{}^\circ \text{ }E\]