1. d3 {Pretty obvious start} 1... e6 2. Qd2 Ba3 {!! Brilliant clearance move to allow the wQ to use the Bishop's diagonal} 3. Qb4 f6 {waiting} 4. Qf8+ {an ingenious choice of sacrifice square} 4... Bxf8
Solution to b):
Header
PGN
1. d3 e6 2. Bh6 {there's that same brilliant clearance idea - except that white does it in this twin!} 2... Qg5 3. Qc1 {white finds a convenient way to dispose of his Q} 3... Qxc1+ 4. Bxc1 {Bishop switchback, just like twin a)!} 4... f6
