Multiply $$( 5 a + 3 ) ( 5 a + 7 )$$

Multiple Choice

Multiply: $$( 5 a + 3 ) ( 5 a + 7 )$$

A) $10 a ^ { 2 } + 15 a + 21$
B) $25 a ^ { 2 } + 50 a + 21$
C) $25 a ^ { 2 } + 35 a + 10$
D) $5 a ^ { 2 } + 38 a + 7$
E) $25 a ^ { 2 } + 20 a + 21$